Power supply The system consists of 'a three-stage network - production, distribution and transmission. The electrical system is responsible for producing electricity using energy like coal and diesel. All devices connected to the system such as motor, circuit breaker, transformer, etc., fall under the umbrella of a power system.
There are six main components of a power system. Let's see what the components are -
The place where energy is generated and configured to be transmitted using a transformer.
Transmits electrical energy from one circuit to another.
The current passes through the transmission line to the sous-stations.
Power is transferred to the distribution line via a support.
It consists of low and medium level power lines that connect to the distribution transformer.
From the distribution line, electricity is distributed to consumers at an appropriate value.
Electrical risks are recorded in the thousands per year, which includes more than 30 cases of death. Therefore, it is essential to stay away from electrical hazards.
Several factors lead to electrical hazards. The factors are described below in brief -
Exposure to loose, frayed and bare wires poses a serious health risk. It is the worker's responsibility to report any cases of damage or faulty cable to thetority as soon as possible. The best way to avoid the risks is to let everyone know and never try to deal if any of them are not legally permitted.
Practicing a safety approach to the use of electrical equipment is imperative. If a worker is not authorized and trained to use a particular electrical device, he should avoid using it. Sometimes energized equipment can appear dead and cause serious death. A worker should also avoid using power tools on a suspended platform unless it is permitted.
All electrical outlets have thresholds. After use, a socket begins to unravel and presents a risk. If overused, an outlet will start to overheat or generate less power than usual. If a worker experiences overheating or sparksIf there is a catch, he should inform the authority rather than deal with it himself.
Water and all other liquids are a good conductor of electricity. Therefore, all workers should always try to keep their electrical equipment away from all liquids. In addition, when using electrical equipment, all workers should dry their hands to avoid electric shock or burns.
Electrical hazards are something that must be taken seriously in a workplace. Every organization must conduct an electrical safety program for all of its workers. In addition to educating them about the hazards, workers should also attend a safety workshop.
Many workers in the workplace do not pay much attention to the risks associated with electricity. Some believe that school-related incidentsCtricity is a part of life and some even think that accidents can never happen to them. What makes matters worse is that some workers believe that health risks are part of their job and cannot be avoided. This type of reckless attitude among employees leads to more work-related injuries. To bring about effective change from the perspective of workers, a safety program is of paramount importance.
In the field of electrical engineering, engineers and other professionals are exposed to electricity indirectly during production, transportation, 'installation and use. These conditions may cause danger if precise safety measures are not taken.
To promote the safety and correct use of the equipment, there are certain rules and regulations formulated by the Bureau of Indian Standards (BIS). BIS follows the following five principles -
BIS has published the following code of good practice for public safety standards to promote the right information, transparency and accountability appropriately to the public.
Now let's take a look at other important codes of practice established by BIS for electrification purposes. The codes are listed in the table below -
The following tablelists the codes of good practice for appliance maintenance -
The following table lists the codes of good practiceques for Motor Control Center maintenance -
The following table lists the codes of good practice for the maintenance of transformers -
The following table lists the codes of practice for the maintenance of batteries -
The following table lists the codes of good practice for the maintenance of alternators -
We will now learn the differentts concepts related to protection against low voltage overloads.
If the line voltage drops to an abnormally low value, the electrical machinery is damaged or unable to start service. Due to the low voltage, the shunt coil on the starter final contact hold solenoid disconnects the motor from the line. After the line voltage is restored, the motor resumes operation. The release of low voltage is unexpected and dangerous. To protect machines, low voltage protection must be provided.
In low voltage condition, temperature protection is called overcurrent protection. There are three major causes of overcurrent. The causes are listed below -
The overload condition occurs when the equipment is subjected to morethan its face value. This results in excessive heat production.
If there is a connection between the line-to-line or line-to-neutral conductors, this causes a short-circuit. This generates a temperature higher than the designated ratings.
If electric current flows from a conductor to an uninsulated l, the n earth fault occurs.
Current flows in the circuit according to the demand of the loads. If the amount of current increases and exceeds the rated value of the electrical equipment, the system is overloaded. The wires or cables may not withstand the higher current. The wires heat up and even melt the insulation. This leads to the risk of fire. Therefore, overload protection is necessary to prevent such accidents.
Now let's see the different signs of low voltage overload. Here are the different signs -
To avoid such problems, fuses and miniature circuit breakers are used as protective devices. In the event of a fault, the fuse should blow and the circuit breaker should open the circuit. It is also important to protect the conductors as well as the equipment against higher currents.
Each cable has a rated current, which is the maximum safe current capability of the cable. This current load capacity depends on the following factors -
The fuse or circuit breaker should be chosen according to the cable size. When the current dThe fault reaches the fuse, it will blow. This gives a temporary overload condition to the cable. The cable must withstand momentary overloads for a very short time. A little overheating cannot create a dangerous level. This is called the Slow Hit Protector.
Fuse and circuit breaker can protect the cable. However, these are not sensitive to protect a small-use device plugged into the circuit. Therefore, these protection devices are built into the devices to protect against overload. External fuses are used in the main service panels or subpanels, but the equipment fuse or circuit breakers protect every part of the electrical equipment that secures the system.
A short circuit condition means that a circuit allows current to flow through an unintended path with a very low electrical impedance. It is a direct contact between two points of different electric potential.
The short-circuit protection system is broken down into the following systems - Phase-to-earth contact Phase-to-neutral contact Phase-to-phase contact Contact between the windings of an electric machine in phase
Direct current system
- Pole to earth contact
- Contact between two poles
There can be n various causes
Main Causes of Short Circuit Circuit
A sudden surge of current is equivalent to one hundred times the working current flowing in the circuit. This leads to damage to electrical equipment. The following two phenomena are responsible for the devastating effects of short circuits -
This phenomenon refers to the energy released in the electrical circuit during the passage of a short-circuit current in the circuit. This thermal effect leads to the causes of a short circuit -
Melting conductive contacts
Damage to insulation
Generation of electric arcs
Destruction of thermal elements in the bil relay
This phenomenon refers to the production of intensive mechanical stresses when the current crosses and results in the condfollowing itions -
- Broken conductors
- Repulsion of contacts inside contactors
- Distortion of conductors in the windings
Short Circuit protection devices
To protect devices and people against the risk of short-circuits, protection devices are used in electrical circuits. These devices can detect faults and trip the circuit immediately before the surge current reaches its maximum.
There are two common protective devices commonly used in every electrical circuit.
The fuse operates once in the circuit and must then be replaced after tripping. It is useful for phase by phase (unipolar) protection. It offers high breaking capacity at low volume, which limits electrodynamic stresses.
The following images showent different types of fuses -
Circuit breakers can be reset either manually or automatically. It automatically cuts the circuit within a short cut-off time and separates the load from the power supply which protects the circuit from damage. Magnetic circuit breaker releases open the poles. Circuit breakers limit both thermal and thermodynamic effects.Operates faster than a fuse.For example, molded case circuit breaker (MCCB), molded case switch (MCS), air / oil / SF6 / vacuum circuit breaker (ACB / OCB) / SCB / VCB).
The following images show different types of circuit breakers:
Characteristics of short-circuit protection devices
We will now learn the different characteristics ofshort-circuit protection devices. The characteristics are shown below -
Break Ca pacity
The maximum value of the estimated short circuit current that can allow the device to break the circuit at a given voltage is called the breaking capacity.
The maximum short-circuit current that can allow the device to reach its rated voltage under specific conditions is called making capacity. It is the rational multiple of the breaking capacity.
Electrical safety - Protection against earth faults
We will now understand what protection against earth faults is. We are going to be focusing on the earth fault.
Earth fault is an inadvertent fault between the live conductor and the earth. When a ground fault occurs, the electrical system is shortedand the shorted current flows through the system. The fault current returns through the earth or other electrical equipment, damaging the equipment. It also interrupts the continuity of the power supply and may shock the user. To protect the equipment and for the safety of the p Fault protection devices are used in the installation.
Protective devices against earth faults
The devices give the trip order to cut the circuit in the event of an earth fault. The fault current is limited and the fault is dispersed by the restricted earth fault protection scheme (REFP). Normally, the earth fault relay, earth leakage circuit breaker and earth fault circuit breaker, etc. are used to limit the fault current.
Earth fault relay (EFR)
It 'sa safety device used in electrical installations.high earth impedance ques. It detects small parasitic voltages on the l housings of electrical equipment. The result is to interrupt the circuit if a dangerous voltage is detected. The EFR is protected against the triggering of transients and avoids shocks.
The following figure shows the earth fault relay -
Earth leakage circuit breaker
The earth leakage circuit breaker detects current leakage directly and prevents humans and animals from injuring themselves due to electric shock.This is a voltage sensing device and was recently replaced by a Residual Current Circuit Breaker (RCCB), which is a current sensing device. It is a special type of latching relay which is connected to the main power supply. When the fault current flows from the live wire to the earth wire in the installation, the bobine of the ELCB detects the voltage and cuts off the power supply. It requires a manual reset process to work again. The RCCB detects the leakage current and sends a signal to trigger the system.
Earth leakage circuit breaker
The earth leakage circuit breaker is a safety device to prevent an electrical accident in the event of a breakdown. The tool is plugged in. This is a fast acting circuit breaker to cut off power when the ground fault occurs within 1 / 40th of a second. It compares the incoming and outgoing current f of the equipment along the circuit conductor. If there is a difference as small as 5mA, the GFCI will limit the current and trip quickly. GFCI does not help much with line contact hazards, but protects against fire, overheating, and destruction of wire insulation.
Restricted earth fault protection scheme
Consider astar-wound transformer, which is protected by a Restricted earth fault protection with EFR protection device as shown in the figure below.
The following image shows earth fault protection with EFR -
When a external fault F1 occurs in the network, I1 and I2 cross the secondary side of the CTs. The result of I1 and I2 will be zero. However, if an internal fault F2 occurs inside the protection zone, only I2 flows and I1 is neglected. The resulting current I2 flows through the earth fault relay, which detects the fault current and protects the restricted part of the winding. The fault current is about 15% greater than the current nominal winding. To avoid magnetizing inrush current, the stabilization current must be in series with the relay.
Electrical safety - Mise to earth
The process of transferring unintentional electrical energy directly to earth via a low resistance wire is called electrical grounding. It refers to the connection of a non-current-carrying part of the equipment or of the neutral of the power supply system to earth, which represents zero potential. The leakage current chooses the simple low resistance flow path. Thus, the electrical system and the equipment are protected from damage.
Types of electrical grounding
Electrical equipment has two non-current-carrying parts such as the system neutral and the equipment chassis. The earthing system is also classified into two types.
The Connection Process Connecting the system neutral to earth through a GI wire is referred to as neutral grounding or system grounding. It is used in winding systemsnt in star, including generator, transformer, etc.
Earthing of the equipment
When the l frame of the equipment is connected to the earth with a lead wire, then this is called equipment grounding. In the event of a fault in the device, the fault current flows to earth and the system is protected.
Grounding is necessary for the following reasons -
To protect the user against electric shock.
The earthing system shows the easiest path to the fault current even after the insulation fault.
It protects electrical devices used in the circuit from short-circuit currents, overvoltages and lightning discharges.
We will now understand the need for grounding by considering the confollowing editions -
Grounding of a system is done during installation to connect the respective parts with electrical conductors or electrodes. The electrode is placed near the ground or below ground level, which has a flat iron riser below the ground. The non-current-carrying parts are connected to the flat iron.
The following figure shows fault current flow without earthing system -
In the event of a fault, the fault current flows from the equipment to earth via the earthing system. Thus, the device is protected against short circuits or fault currents. At the moment of the fault, the voltage of the electrode increases and equals the resistance of the electrode and earth fault.
The following figure shows the fault current flow withc an earthing system -
Earth resistance measurement
The earth resistance of an electrode is measured by the potential drop method. The total configuration is shown in the figure below, where -
E is the earth electrode to be tested
P & C are two auxiliary electrodes placed at an appropriate distance from E
I am the amount of current flowing between E and C
V is the voltage measured between E and P
The following Figure shows the configuration for measuring earth resistance -
There is no appreciable effect on the resistance of E, if C is an adequate distance from E. As the current in the electrode P is very small, the electrode also has a negligible effect on resistancethis. Now varying t At the distance from the electrode P to E, the resistance is measured.
The following figure shows the real resistance of the curve R vs d -
According to the figure, the part of the curve is marked R of E, which is an almost horizontal slope in the curve. The upward slope indicates the effect of the resistance of C. For the calibration of the ground measuring earth tester, the ratio is directly used.
The Grounding must follow the rules and regulations for risk reduction according to the following standards.
Indian standards: IS 3043- Code of practice for grounding (latest)
National Electricity Code (NEC): 1985 of BIS
IEEE Guide for Safety in earthing of AC substations No. ANSI / IEEE Standard, 80- 1986.
Proper field inspection and investigation is required prior to installation. An organization chart must be followed for the different stages: Inspection & Investigation - Design - Test - Installation - Maintenance - Preparation of the report .
Electrode resistance, The resistivity of the soil is measured periodically and a megohmmeter test should be performed.
Do not use copper or aluminum wire as a substitute, paint, enamel and grease on the electrode. Protect the electrode wire from mechanical stress and corrosion.
Appropriate training and management can reduce the risk factor.
Types of supply system
We will now learn about the different types of supply system. Before we start, we need to know what a diet is.
The supply of electrical energy to uno electrical load is called power. The main function of the power supply is to convert the electric current from a source into the correct voltage, current and frequency to power the load. Electrical outlets, energy storage devices such as batteries, fuel cells, generators, solar energy converters are generally referred to as energy sources.
The power supply is classified into different categories. In our next sections we will see what the different categories are.
DC power supply
Such type of power supply provides constant DC voltage to the loads. It can be powered from either DC source or AC source.
AC-DC power supply
AC power can supply DC power using a rectifier, which converts the output voltage of the transformer into a voltage continuous variable. DC voltage passes through a filtre electronic, which transforms it into an unregulated direct voltage. There is also a register in series with the output to limit the load current and the final output power is supplied to the load.
Switching power supply (SMPS)
The main input is converted to direct voltage via a rectifier and a filter, then turned on and off at high frequency (10 KHz - 1 MHz ) by an electronic switch. It has a security function to protect the devi ce and the user.
The linear regulator converts a variable DC voltage into a constant. There is a current limiting function to protect the power supply and load against overcurrent. It is independent of the fluctuation of the input voltage and the impedance of the loads to provide a constant value.
AC power can be taken from the main power transferred to the teDesired nsion with using the step-up and step-down transformer. This power supply is
Programmable power supply
A PPS allows remote operation via an analog input or a digital interface such as RS 232. Controlled properties include voltage, current and frequency (in the case of alternating current).
Uninterruptible power supply
The inverter has a function to take power from two or more sources simultaneously. It is used as a back-up power supply because it takes over the load in the event of main power drop or failure. The process is so fast that the charging never suffers an interruption.
High voltage power supply
HDPS supplies most of the power, either hundreds or thousands of volts for applications above 20KV. It includes a tens multiplierion or high turn ratio, high voltage transformer or both to produce high voltage.
Power supply principle
In modern power plants, the electricity production is at 25 KV and it is transformed at 400 KV. The number of generator sets are designed to provide the flexibility of power required for seasonal variations in loads. The principle is to supply power to any consumer with a ring system and fed in both directions carefully with adequate protection and loss of power.
The following image shows the distribution of the power supply from the power plant to the consumer -
Trai the qualified employee must be engaged in the practice of electrical work. Each electrical work must follow the following codes and standards, including -
The practice of external power supply is applicable for computer, electric vehicle, welding use, aircraft power supply and plug-in adapters.
Power supply characteristics
The power supply electrical characteristics refer to the quality of the power supply. Form factor Ripple factor Rated power Rated voltage Operating voltage range Input frequency range Efficiency Load regulation Line regulation Transient response Waiting time Protections Maximum inrush current
1. What kind of power supply requires an analog input?
a) High voltage power supply
b) Programmable power supply
c) Switching power supply
d) AC-DC power supply
2. Which of the following is not required in the AC-DC power supply?
3. Which of the following is not characteristic of the power supply?
a) Trigger time
b) Inrush current
c) Line regulation
d) Ripple factoron
Electrical Safety - Cables
A cable is a group of wires wrapped in a sheath t hat ensures a smooth electrical supply. It should be installed with care following the National Electrical Code and the National Building Code for various electrical applications.
There are over 20 different types of cables depending on the design and application. Consider here some important types -
Non-llic sheathed cable (NM cable)
These cables have a flexible plastic jacket with two to four wires which are commonly used for indoor residential wiring and special varieties are intended for underground and outdoor wiring.
Underground power cable (UF cable)
The wires of these cables are bundled and integrated into the flexible material. They are useful for outdoor lighting and in-ground applications.
Metal sheathed cable (BX cable)
There are three stranded copper wires insulated with a crosslinked polyethylene and PVC jacket. These cables are used for outdoor applications and high stress installations.
The following images show the different types of cables -
Multi-conductor cable (MC cable)
More than one individually insulated conductor. Outer insulation gives extra security. Different varieties of MC cables are used in homes and industries For example, multicore audio "snake cable".
Coaxial cable (Heliax cable)
A tubular insulating layer with a conductive tubular shield protects the inner conductor of the cable As the two internal sheaths share the same geometric axis, the name coaxial is justified. It is used to carry signals from television and connect video equipment.
Unshielded twisted pair (UTP) cable
UTP cable consists of two twisted wires with solid copper cores and not individually insulated. These are often used in phones, security cameras, and data networks.
It has different conductor wires parallel to each other on a flat plane. Ribbon cables are applicable to low voltage applications such as computers and its peripherals.
Direct buried cable (DB cable)
This is specially designed coaxial cable or bundled fiber optic cables, which have many layers of l sheath tape, thick rubber liners and wire reinforced adhesive tape wrapped in shock absorbing gel. This is considered a popular choice for transmission and communication requirements.
Two-wire cable (TL cable)
TL cable consists of two wires which are generally used in transmitting a signal from the antenna to receivers like television and radio.
There are two individually insulated conductors, which are used in low frequency DC or AC applications.
Twisted pair cable
The inner insulated wires of the TPC are twisted or intertwined; otherwise, it is the same as the coupled cable.
Importance of thermal resistance
Thermal resistance is the optimum temperature at which the insulation cable melts. It depends on the wiring area that the thermal phenomenon has taken into account when designing the underground electrical network. In an underground electrical network, the temperature of the cable core must not exceed the maximum operating temperature of the cable (65 ° C).
The following figure shows the variation of the temperature of the cable core with the increaseation of the thermal conductivity of the ground -
Thermal conductivity varies depending on the material used in the layer of the cable because the cable needs to dissipate heat in its surroundings.
| Cable layer || Material || Thermal conductivity () |
| Conductive || Copper || 400.00 |
| Isolation || XLPE || 0.3232 |
The thermal conductivity of soil changes the intensity of heat transfer from the power cable. As the conductivity increases, the soil receives heat faster and the temperature of the cable decreases.inue. The conductivity of the soil depends on the water content (caused by rains or droughts) and humidity. Temperature distribution should be done efficiently while working in the underground power grid.
Now let's consider some safety precautions -
Make a safety plan, which includes emergency activities, evacuations in accordance with codes and standards.
Professional and trained electricians should be employed who understand safety protocols and the surrounding work environment.
Workers should use non-conductive gloves, safety glasses, footwear and protective clothing to protect themselves from electrical hazards.
Maintenance and testing should be done periodically.
1. What material isused to cross-link the core in the l sheathed cable?
2. Which cable is suitable for cameras and data networks?
3. What happens to the cabin the core temperature with increased thermal conductivity of the ground?
c) No change
d) Cannot be predicted
Classification of zones at risk
Electrical equipment can generate heat, arcing and sparks under normal and abnormal conditions. This increases the risk of fire and explosion in the presence of flammable, combustible and flammable gases, vapors, liquids, dust or fibers. A few places were also considered dangerous. In accordance with NFPA 497 and articles 500 and 501 of the NEC, hazardous areas are classified into different categories. Let's find out about the different categories in our following sections -
Class I location
This location contains flammable gases, vapors or liquids, which create a fire or fire hazard. explosion. The NFPA 497 Class I Hazardous Product Classification Practice (Reference 2) provides locations.
The concentrations inflaflammable gas, vapors produced by a flammable liquid or vapors produced by a combustible liquid exist at this location under normal operating conditions.
Flammable concentrations of flammable gases, vapors produced by a flammable liquid or vapors produced by a combustible liquid exist in this location under abnormal operating conditions.
There are four groups based on their physical properties -
- Group A - Acetylene
- Group B - Hydrogen
- Group C - Carbon monoxide
- Group D - Gasoline
Class II location
Fire or explosion hazard exists due to combustible dust in a Class II location. NFPA 499 specifies electrical / electronic equipment for safe and correct installation ina class II location.
Combustible dust is present in air under normal operating conditions sufficient to produce explosive mixtures. These are moderate to dense dust clouds, which form a dust layer greater than 3.0 mm.
Combustible dust is present in the air under abnormal operating conditions, which is sufficient to produce an explosive mixture. These are not visible dust clouds, which form a dust layer smaller than 3.0mm.
Combustible dust is grouped into three types based on their physical properties.
- Group E - Titanium
- Group F - Carbon black
- Group G - Polymer of nylon
Class III location
Risk of fire or explosion exists due to flammable fibersin this location.
After classification of hazardous areas, explosive atmospheres are
For gas, vapor and mist -
This explosive atmosphere consists of a mixture with air of substances dangerous in the form of gas, vapor or mist continuously or for long periods or at regular intervals.
A mixture with air of hazardous substances in the form of gas, vapor or mist is sometimes present in normal operation in this classified atmosphere.
The mixture of hazardous substances is in gas, vapor or mist form and only persists for a short time.
For dust -
This atmosphere consists of explosive materials in the form of acloud of combustible dust in air continuously, or for long periods or at intervals.
There is sometimes explosive combustible dust in cloud form in the air during normal operation.
Explosive combustible dust is present as a cloud in air and persists for a short time.
Characteristics of risk areas
Let us now see the characteristics of risk areas. The characteristics are as follows -
Properties of hazardous substances
It includes the boiling point and the flash point of any flammable liquid, gas or vapor, which can be lighter or heavier than air.
Size of potential release
This is a consequence of bad circumstances where a quick rescue is dangerous. For example, an LPG cylinder or canister.
Temperature and pressure
When certain substances do not form an explosion without heat and pressure.
Adequate ventilation can prevent fire and explosion.
Choice of electrical device to use
The equipment is built according to standards to avoid being a source of ignition. These are classified into 1, 2 and 3 depending on the level of the area depending on the relevance of the application. Mechanical equipment is not certified for use in hazardous area. If categorized equipment is not available, the lower category can be used in combination with other protective measures.
1. What flammable materials exist at location III?
The place where combustible dust in the form of a cloud in the air is present in normal operation is called ______.
a) Zone 0
b) Zone 21
c) Zone 2
d) Zone 22
3. Which one is not the characteristics of the explosive atmosphere?
a) Size of potential version -
b) Ventilation -
d)Temperature and pressure -
Gas / duct / fiber measurements
It It is very important to take into account safety measures when working with gas, ducts, fibers. It is recommended that a person working with these wear the required safety gear and carry all the necessary tools.
Gas safety measures
The incident rate has reached 6% due to electrical enclosures at oil and gas companies around the world. Safety measures play an essential role and help to avoid electrical hazards.
For reliability and safety reasons, it is necessary to periodically check and maintain the electrical system in good condition after installation.
Proper care and experience is required for expansion, modification and refurbishment of existing facilitieses when working with a live factory.
It takes a professional to choose the perfect electrical equipment to install in a gas industry. For example, an HRC fuse is suitable for these industries instead of a kit-kat fuse.
The installation, design, testing and maintenance of electrical equipment must meet the standards of the respective nationalities to guarantee the expected quality as well as safety.
Conduit / Fiber Safety Measures
The conduit (s) are the cable tray and protect them.
Electrical conduits must follow the standard specifications of -
- ASTM F2160
- NEMA TC7
- UL 651A & B and UL 2024
- National Electrical Code (chapter 9)
It is essential to focus on the diameter of the duct ∓ inner duct, number of ducts ininterior, length and direction, the composition of the duct, the coefficient of friction, combination of blocking, traction speed, temperature, elevation, weight of the internal duct, mechanical stress, tension and radii of curvature, etc.
Trained professionals should choose conduits as per the environmental requirement, including underwater, underground, exterior or interior location. Use symbols for underground wiring that can keep people from digging and dealing with accidents.
The electrician should use a tensiometer, cable lubricants and the required electrical equipment.
Safety measures related to fiber material
Fiber optic cables must be handled with care with a good knowledge of the radius of curvature, and twist of the cable.
Use a laser beam to find damage in theoptical communication cable.
Do not stick broken cable ends or drop pieces of fiber on the ground. Avoid skin contact with the fiber material.
Remember not to eat or drink anything near the installation area.
Group classification of flammable gases / vapors
Flammable gas or vapor can be ignited by an arc or spark in the electrical system and lead to dangerous accidents. There are four Class I group classifications in section 500-5 (a) according to NEC.
Group A: Acetylene
Group B: Hydrogen and gases equivalent to a dangerous nature
Group C: Ethyl ether or gas or vapors equivalent to a hazardous nature
Group D: Gasoline, alcohol, acetone, natural gas and similar materials
These groups were constituted according to the levelhazardous water associated with explosion pressures of the specific atmosphere. In addition, these engineers should follow the "Practice for Classification of Flammable Liquids, Gases, or Vapors" in NFPA 497.
Group Classification of Ducts
There are different types electrical conduits or conduits used for various applications.
Rigid Galvanized Conduit It
Thick galvanized steel tube protects electrical wiring and becomes an electrician's choice in commercial and industrial applications.
Metal electrical tubes
Such conduits are made of steel or aluminum and limited to a specific radius for bending. It is very popular in commercial, residential and industrial buildings.
Non-llic electric tubes
It is moisture resistant and flame retardant and it is easy to bend by hand due to its flexibility.
Metal duct flexible
It is known as "Greenfield of flex " meaning it does not maintain permanent curvature. It is recommended for dry areas.
Liquid Tight Flexible Metal Conduit
These are covered with waterproof plastic coating which is applicable for general wiring in wet or damp locations.
Rigid l conduit
It is made of stainless steel or coated aluminum which prevents corrosion.
Flexible non-llic liquid tight conduit
These are the flame retardant type which is recommended as a raceway for the installation of approved conductors (600 volt gauge).
It is used in large amounts of water areas and areas prone to corrosion as it prevents corrosion.
It is resistant to moisture and corrosion, which also has the coefficient of thermal expansion.ue the highest.
Based on the Electrical conduits of design and shape are classified as follows -
- Individual round pipe
- Extended plenum
- Reduction trunk
- Multiple return air
The following figure shows the differences between the supply duct systems -
The following figure shows a typical conduit connection and a -
- Reducer Tee
1. Class I group classification of flammable gases / vapors / liquids are described in ______.
a) NFPA 70
b) NEC Article 500
d) None of these
2. Which group does flammable gas hydrogen belong to?
a) Group D
b) Group C
c) Group B
d) Group A
3. Which of the following is known as “Greenfield Flex”?
a) Liquid-tight flexible l duct
b) Galvanized rigid conduit
c) PVC C corrugated
d) Flexible l duct
Classification of temperature
We will now learn the classification of temperature. In addition, we will also understand the importance of temperature.
Importance of temperature
Temperature is one of the most essential factors in process engineering to detect a hazardous condition in the plant and in equipment. The Integral Safety Level (SIL) measures the function of the safety instrument. SIL specifies a target level of risk reduction. The 615081 standard of the International Electrotechnical Commission (IEC) assigns SIL to devices, which are able to eliminate the device fault and detect the fault.
Classification of temperature for electrical equipment
There are insulation classes, which allow a maximum allowable temperature for the safety of devices. Electrical instruments can be reduced by an insulation technique of greater thermal endurance.
The fol The table below shows the maximum allowable temperature and the materials used for different types of insulation -
| Isolation classes || Maximum authorized temperature (ᵒC) || Material used |
| Y || 90 || Cotton, silk or paper |
| A || 105 || Class Y materials reinforced with impregnated varnish or insulation oil |
| E || 120 || Combination of different materials |
| B || 130 || Inorganic material with adhesives |
| F || 155 || Class B materials upgraded with adhesives, silicon and superior thermal endurance varnish |
| H || 180 || Inorganic material bonded with silicon resin or adhesives of equivalent performance |
| C ||> 180 || 100% inorganic material |
Temperature classification for hazardous areas
The temperature classification describes the threshold temperature for the hazardous area. The value of the minimum ignition temperature is classified from T1 to T6. This temperature classification identifies a temperature that an instrument will produce at room temperature (40 ° C). The temperature identified is called maximum surface temperature .
T1 - The minimum ignition temperature> 450 ° C and the maximum surface temperature generated by the The instrument is 450 ° C.
T6 - The minimum ignition temperature> 85 ° C and the maximum surface temperature generated by the instrument is 85ᵒ C.
| Temperature classificationature || Minimum ignition temperature || Temperature Maximum surface temperature |
| T1 ||> 450ᵒC [842ᵒF] || 450ᵒC [842ᵒF] |
| T2 ||> 300ᵒC [572ᵒF] || 300ᵒC [572ᵒF] |
| T3 ||> 200ᵒC [392ᵒF] || 200ᵒC [392ᵒF] |
| T4 ||> 135ᵒC [275ᵒF] || 135ᵒC [275ᵒF] |
| T5 ||> 100ᵒC [212ᵒF] || 100ᵒC [212ᵒF] |
| T6 ||> 85ᵒC [185ᵒF] || 85ᵒC [185ᵒF] |
If there is a measurement problem that occurs with the hazardous area instrument, it can be repaired. The repair section has three basic categories.
Factory repair only
The device must go through safety test procedures and be returned to the factory.
It is difficult to practically train the technicien end user. If there is any difficulty in solving the problem, authorized factory personnel should be employed.
End User Field Repair - This involves direct replacement in terms of form, fit and function.
The temperature measuring instrument is designed in accordance with safety standards. In an industrial environment, temperature measurement is necessary for a wide variety of needs and applications. A large number of sensors and devices meet this demand. The measuring instruments are as follows -
- RTD (resistance temperature detector)
1. In which class of insulation Is inorganic material with adhesive used?
a) Class E
b) Class Y
c) Class B
d) Class A
Explanation - From table 1, the inorgan Material with adhesive can only allow insulation at 130 ° C, which refers to the type of class B.
2. What is the maximum surface temperature (in ᵒC) in temperature type T4?
c ) 200
Explanation - According to Table 2, the least dangerous is a temperature classification T4 which allows 135 ° C of maximum surface temperature to create a hazard.
3. Which of the following isn 't a temperature measuring instrument?
Explanation - Thermocouple, RTD and thermistor are the temperature measuring instrument but the barometer measures atmospheric pressure.
Protection against meteorological complexities
It has now become common that in case of bad weather like a storm or heavy rains, there is a loss of power or electricity. It affects the masses in general. And people in coastal regions are most affected in the event of a power outage due to flooding. 67% of cases of blackout are the result of natural calamities such as lightning, snowfall and wind. To minimize costs and mitigate outage problems, the protection of electrical assets was borncessionary.
Protection of the electrical network
In this section, we will see how to protect the electrical networks against natural disasters.
For critical systems, the inverter and the back-up generator must be installed and maintained correctly. If the power is removed from the network, the backups are used. Regular maintenance service guarantees the reliability of the equipment and a safer working environment.
Power grid design
Electr Correct The ical design minimizes voltage transients generated in the event of a lightning strike. An electric model should be tested in all possible scenarios; faults and weaknesses in various fields are to be expected. proper design should provide -
- alternative paths
- automatic load transfer
The suppliesbackup and alternate paths should be tested periodically. Consider testing the following -
the state of the backup equipment
system logic in case of failure or for new installations
response of site personnel in emergency situation when power supply fails
Data management and analysis helps predict problems, find a solution to avoid problems or resolve a problem. problem already occurred. The management system focuses on the following two areas -
Failure management system
The OMS system provides data and information from a variety of sources, faults , allowing maintenance and the engagement of electricians to repair and restore.
Asset management system
A history of the assets of the installation, the cycle ofExpected life and technical specifications must be maintained to ensure a reliable and resilient network.
Protection against extreme weather conditions
Extreme weather conditions refer to lightning which could be catastrophic for electrical devices. Note the following points to ensure the security of your devices.
Electrical surge can fry a circuit board of electronic equipment like TV, laptop and audio system etc. . A top notch surge protector can be used to prevent damage.
Three characteristics should be considered when purchasing a high quality Surge Protector (SP) -
Low clamping level - It takes a voltage to trigger the SP and to divert the electricity to the ground
Poor response time - It takes nanoseconds to respond to the surge
High surge capacity - It takes a certain amount of voltage that a SP can take and work properly
It is not necessary to depend on the warranty of SP. Attach a status check light to it that indicates the last surge.
Avoid overloading a surge protector, which can increase the risk of damage to electronic equipment.
Standards against dirt and water
According to standards 60529 of the International Electrotechnical Commission ( IEC ) , the international protection marking classifies the degree of protection that is provided against intrusion, dust, accidental contact and water by the mechanical box and the electrical box. The Ingress Protection (IP) defines from which the equipment is protected under conditinormal ons. The first number indicates the protection of the equipment against solids. The second number indicates the protection of the equipment against the harmful ingress of
The following table lists the IP codes and their meanings -
| 1st digit || Protection against solids || 2nd digit || Moisture protection |
| 1 || Hand Protected: protection against solid objects over 50 mm in diameter || 1 || Anti-drip against vertical drops of water |
| 2 || Protection of the fingers: protection against the object> 12.5 mm || 2 || Anti-drip when tilted up to 15ᵒ |
| 3 || Protected tool: protection against object of diameter or thickness > 2.5mm || 3 || Rainproof / splashproof when water falls at an angle up to 60ᵒ |
| 4 || Protected wire: protection against objects with a diameter or thickness> 1.0 mm || 4 || Splash resistant against splashing water from all directions |
< td class = "ts "> 5
| Protection against dust accumulation: protection against dust interfering with operation || 5 || Resistant to jets when water is projected through a nozzle (diameter 6.3mm) at pressure from any direction |
| 6 || Protected against ingress of dust: protection against ingress of dust || 6 || Resistant to the jets in case of water projection through a nozzle (Ø 12.5 mm) at a pressure from any direction |
| || || 7 || Waterproof in case of temporary immersion in water |
| || || 8 || Pressure tightness in continuous immersion in water |
The The following table lists the letters that define dangerous parts. Other letters provide additional information relating to the protection of the equipment.
| Level || Dangerous parts |
| A || Dos of the hand |
| B || Finger |
| C || Tool |
| D || Wire |
The following table lists some letters in IP codes -
| Letter || Meaning |
| F || Oil resistant |
| H || High voltage device |
| M || Device moving during water test |
| S || Device stationary during water test |
| W || Weather conditions |
1. Which device requires nanoseconds of time to respond to the surge?
a) Device with low level of clamping
b) Device with low response time
c) Device with high surge capacity
d) None of the above
To justify its name, the low response time device only requires nanoseconds to respond to the overvoltage, recognize the fault and instruct the protection device to trigger.
2. The IP codes follow the standard of __________.
The International Electrotechnical Commission of Europe describes the protection against the penetration of mechanical and electrical equipment boxes.
3. What is the significance of the IP56 enclosure?
a) Protection against finger insertion and vertical dripping in water
b) Dust resistant and can be submergedé in water
c) Protection against dust and high pressure jets of water from any direction
d) None of the above
In IP56, the first digit 5 refers to protection against dust and the second digit 6 refers to protection against high pressure water jets Any direction . By combining the two digits, the result refers to option C.
Design features of safe electrical equipment
We will now learn the design features of safe electrical equipment. safe electrical equipment. Let's be understanding what the equipment review is.
Examination of the equipment
It is important to examine the electrical equipment, which can cause serious physical hazards. It ensures that the equipment is free from hazardous reconnus. Note the following important points for the safety of the equipment.
Suitability of equipment is identified in accordance with labeling and specifications
Mechanical resistance and durability
Heating effect depending on the state of the zone
Practical protection of employees
Use of Electricity Equipment
Electrical equipment should be installed in accordance with the instructions given, including type, size, voltage, current capacity and specific use. Devices should only indicate the goal after they have been reviewed and arrangements have been made for it to meet that goal. Even a small device has its own importance. For example, disconnecting a switch will open a circuit and stop the flow of electricity.. The equipment should be resistant to weather, chemicals, heat, corrosion or any hazardous environment.
Working with electrical equipment
It is very important that a person working with electrical equipment is qualified to work on the equipment. Working on live parts always creates hazards without using personal protective equipment. Clean the cutting material on the floor after work. There must be a storage room to keep the equipment safe. The workspace should be large and well ventilated. An electrician must meet NEC, NBC, NFPA and IEC standards, etc.
Safety requirements for electrical equipment
Verification and testing will ensure the safety and quality of the equipment. Confirmation of equipment in accordance with product standards is the primary importance of an installation. The focusearth of the equipment is necessary to divert the fault current, which will be permanent and continuous. High temperature can lose the continuity of the earth fault path. Thus, an earth leakage circuit breaker should be used to prevent injury from electrical wiring. This would provide additional protection to the device. The breakage of the cable insulation occurs simply by aging. It can cause shock, burns and fire. Periodic maintenance of electrical equipment is therefore necessary. Maintenance predicts and prevents damage. The equipment should be protected from lightning by installing the surge protection system.
The best method of protection is "automatic disconnection of power" which can be provided by grounding the system. An electrician must have sufficient knowledge of the standardized system (TT, TN and computer system). The pProtection against overloads, short circuits and earth leakage currents can also protect the device from damage. Each item must be well insulated and packaged.
Standards for the design of electrical equipment
Certain internal standards must be observed when designing electrical equipment. The standards are as follows -
International Electrotechnical Commission (Europe)
Institute of Petroleum ( United Kingdom)
International Organization for Standardization (worldwide)
British Standards Institution (United Kingdom)
American Petroleum Institute (USA)
Engineering Equipment and Materials Users Association (United Kingdom)
Electricity Council (United Kingdom)
Institute of Electronic and Electrical Engineering (USA)
1. Which ofThe following items are not a fact for the safety of the equipment?
a) Mechanical resistance and durability
b) Electrical insulation
c) Equipment color
d) Heating effect in the conditions of the area
To examine the safety equipment, mechanical resistance, durability , the electrical insulation and the heating effect in the state of the area are some points to consider. However, it does not depend on the color of the equipment.
2. Which device prevents injuries caused by electrical wiring?
The dEarth leakage circuit breaker detects the fault and temporarily shuts off the circuit within milliseconds. This prevents injury from electrical wiring.
3. What organizational standard does each manufacturer follow to design electrical equipment?
d) All of the above
A manufacturer should focus on the specification, type, safety, testing, application and quality of equipment. Therefore, the manufacturer should choose the standards of the International Electrotechnical Commission (IEC), the International Organization for Standardization (ISO) and the Institute of Electronic and Electrical Engineering (IEEE) to design electrical equipment.
Electrical safety - Test Certifications
NewNow let's understand what electrical safety test certifications are. Let's start with the concept of certification of electrical products.
Electrical Product Certification
A product must pass performance test, quality assurance test, and meet the specifications of the certification program. The certification system includes
Federal Communications Commission (FCC)
Telecommunication Certification Body (TCB ) program
Energy Star Program of the Environmental Protection Agency
International Rules Commission Electrical Equipment Product Safety Certification Body System Approval
Green IEQ Certification Program by Product Analysis Services materials
Global accreditation bodies
All recognized bodies are listedried for accreditation to ISO 65 by the International Accreditation Forum (IAF). Recognized organizations are -
American National Standards Institute (ANSI)
Accreditation Board (a ANSI sub-division)
American Association for Laboratory Accreditation (A2LA)
International Accreditation Service (IAS)
United Accreditation Foundation (UAF)
Technischer Überwachungsverein (TÜV) - Germany
Korean Accreditation Bureau (KAB) - Korea
Certification of safe electrical work
The system regulatory promotes safety by complying with standards. The work must be controlled and enforced through the certification system. Therefore, certification is required for such work. The Energy Supply Act 2006 defines two different classes of electrical works.ques - controlled work and restricted work . The scope of the two works was established by the Energy Regulatory Commission.
Controlled electrical work
Some electrical work requires experienced people for safety reasons. Controlled work falls within the scope of the control system initially. A registered electrical contractor must perform the certified controlled work or a safety oversight inspector may also perform the work. The certificate describes the confirmation that the electrical work has been tested correctly. Safety verification with national standards in accordance with national wiring rules is an important category of certification. The work must be sufficiently important in the context of electrical safety and must be controlled by issuing a certificate of completion. The probability louser a similar representative the lacing of switches, sockets, lights to an existing circuit must be carried out in accordance with the technical rules. Such work defines the scope of the controlled work. This involves installation, commissioning, inspection and test work as defined in part 7 of the national wiring rules ET101 and ET105. The inspection of electrical installations must confirm the regulation 89 of Sl. N ° 732 of 2007.
Restricted electrical works
The current scope of the restricted works was decided in 2013. It involves the electrical installation in all the places listed in the part 7 of the national rules Electrical installations. Inspection, testing or certification of existing electrical installations is described in chapter 62 of the national rules for electrical installation. This work is only applicable to domestic environments.
In this section, we will learn more about the equipment tests undertaken by different recognized organizations -
The Central Power Research Institute tests electrical equipment such as transformer, reactor, switchgear, cable, conduit, capacitor, surge protector relay, insulation and renewable energy products and thus generates a test report.
BSI provides Certification Board (CB) report for devices, computer equipment, control and wiring accessories, electronic components, medical equipment, cables and the environment.
The Electrical Research and Development Association shows excellence in testing, calibration, R & D with the support of the Research Council Scientific and Industrial (CSIR) for different products such as cables, transformer oil, electricity meterenergy, switchgear, T & D lines, lamps & lights, dielectrics, polymers and photovoltaic c ell.
ITC Pvt Ltd. provides testing services for input protection, LED products, battery, PV module, cable gland and household appliances, etc.
The National Recognized Testing Laboratory is a private organization under OSHA and guarantees OSHA electrical safety standards. It authorizes the manufacturer to apply the registered certification for a particular product.
The testing department of any organization should follow several IEC standards such as -
| Sr.No. || Standards and test equipment |
| 1 || |
| 2 || |
| 3 || |
| 4 || |
Lamp control gear
| 5 || |
| 6 || |
| 7 || |
Audio video and similar product
| 8 || |
Low voltage switchgear and electrical switchgear assemblies
| 9 || |
Rotating Electric Machine
1. Who can include an organization as an accrediting body worldwide?
All recognized organizations are listed for accreditation to ISO 65 by the International Accreditation Forum (IAF).
2. What is the name of the recognized laboratory by OSHA?
d) None of the above
The nationally recognized testing laboratory is a private organization under OSHA and guarantees safety standards electric OSHA.
3. What is the standard test code for LED luminaires?
a) IEC 60065
b) IEC 60595
c) IEC 60601
d) IEC 60034
Any organization should follow LED luminaire testing services according to the 60595 standards of the International Electrotechnical Commission.
Procedure for marking unprotected equipment
We are now going to discover the procedure for marking unprotected equipment. To get started, we'll take a look at industry security practices.
Industry Safety Practices
Now let's take a look at the safety practices in the electrical industry.
Select device tuning in accordance with the intended purpose and use within the specified limit. Do not use the external auxiliary device
Instructions and safety
Contact the technical assistant for how to use the device according to the guidelinessecurity labels and tags.
Refer to Material Safety Data Sheet (MSDS) and understand the processing characteristics of the material. Ground equipment and install protective devices.
Use safety devices such as guards, interlocks and protect yourself with personal protective equipment. Make sure you see the signs of potential appropriately.
Maintenance and repair
Perform scheduled maintenance at regular intervals and confirm proper operation of the device. In case of failure, replace or repair it.
Equipment safety information
Specific conditions that equipment can withstand are listed in the equipment manual or on the equipment. We must also observe some precautions while handli ng and working with the team.electrical equipment.
Avoid open flames in site area
Check the pressure daily to protect the 'equipment against wear, damage or leakage
Do not point the dispensing weapon at anyone
Do not remove the melted hot melt wire with bare skin
If you encounter a disaster, immediately consult a doctor
Shut down the equipment safely, as the level of shutdown varies from device to device.
General Safety Warning and Caution
Each piece of equipment is accompanied by warning and warning symbols supplied by the manufacturer. It is important that an electrician understands warnings and symbols and handles the equipment accordingly.
The following table shows some security labels and their deion -
| Sr.No. || Security label || Deion |
| 1 || || |
Disclaimer - Risk of electric shock. This can cause injury or damage to the equipment if not observed properly.
| 2 || || |
Warning - Potentially dangerous situation. cause serious injury or death.
| 3 || || |
Warning - Potentially dangerous situation. It can cause slight or moderate injury.
It is recommended that you understand the type of equipment. It is also important to know the location of the equipment and what to keep away.
HM - Hot Melt - Attention: To stay away from the hot surface. If hot l comes in contact with a hot surface, it can lead to disaster.
PC - Process control - Warning: untrained or inexperienced personnel can lead to property damage and personal injury.
CA - Cold adhesive - Warning: do not use high pressure. It can release cold adhesive and cause personal injury.
Approved symbols present on devices
The following table lists some approved symbols present on devices
| Sr.No. || Icons || Meaning |
| 1 || || Corrosive product |
| 2 || || Product dangerous for health |
| 3 || || Toxic product |
| 4 || || Product harmful to the environment |
| 5 || || Explosive product |
| 6 || || The product meets European safety requirements |
| 7 || || Restriction of certain substadangerous substances in electrical / electronic equipment |
|8 || || Very low safety voltage |
Marking on site
In this section we will go to the different brands at a site and understand what they mean.
Barricades and Signage
There are different types of barricades used at the site. The following table shows some barricades -
| Type || Deion || Example |
| Warning || Access allowed but attention required. It highlights the danger zone. || |
| Danger || Access authorized on instruction of authority. Restricted area: hot work, falling object, unprotected edge. || |
| Do not enter / Electrical work || Used for switchboard, maintenance of distribution lines. || |
| Radiation || Access authorized under the instructions of the radiation protection officer. || |
| Incident scene || No has access for any unauthorized person in the event of an incident. || |
| Mesh Barrier / Flag Bunting || It is used to highlight the limit of the work area. || |
| Solid barricade || This sign means establishing a safe distance from the plant or equipment || |
1. What must be understood to understand the equipment at installation time?
d) None of these ci
The Safety Data Sheet (SDS) is referenced before installation of 'equipment.
2. What barricade is / are necessary to highlight the limit of the work area?
a) Barrier mesh
c) Bunting flag d) Both A and C
According to safety standards, barrier mesh and flag bunting are used to highlight the limit of the workplace.
3. Which symbol represents the product harmful to the environment?
Each symbol defines a product such that A represents dangerous for health, B represents harmful for the environment, C represents a corrosive material and D representsan explosive material.
Maintenance of unprotected equipment
We will now understand the maintenance of unprotected equipment. Here we will also delve into the different types of maintenance.
Types of maintenance
The technical actions govern the normal operation of the equipment which is The refractometer measures the concentration of the fluid.
Preventive / Predictive Maintenance
Preventive maintenance does not mean to maintain the equipment at the time of the malfunction but to avoid breakdowns before they happen. It is applicable to avoid the breakdown. This type of maintenance is performed over a period of time and then it is called Scheduled Maintenance which reduces the risk of equipment malfunction and degradation. Preventive maintenance focuses on the type of equipment that manages to adopt maintenancepredictive and conditional.
Predictive maintenance defines the condition of equipment through the use of The thermistor measures the temperature.
When a fault, failure or malfunction is detected, corrective maintenance is applied to the equipment. As the name suggests, it is useful for correcting problems. It cannot be predetermined as preventive maintenance. It focuses on infrastructure and equipment. This is emergency maintenance. This maintenance must be carried out efficiently in the equipment.
Routine preventive maintenance should be checked to prevent damage to electrical equipment. Consider the checklists below to follow preventive checks -
Clean the machine at regular intervals and apply oil to the unprotected l surface.
Lubricate the Machine
Proper lubrication can protect the turret, spindle, dry gears, bearings and oil reservoir and protect from wear and tear. corrosion.
Skim off the oil from the machine
The oil skimmer is used on the surface of the machine to create an ideal potting soil and removes dermatitis, dry skin, bad odors and bad tool life.
Monitor machine cutting fluid
A refractometer monitors the concentration of water-based fluid every week. Another kit checks the PH level. Play and roster should be checked quarterly.
If there is a maintenance problem, the equipment should be repaired for smooth operation. The art of repair installationis responsible for repairing and modifying all types of electrical equipment parts. Some parts of the devices should be checked frequently and repaired accordingly.
The repair of leaks, bearings, housings, radiator fins, gaskets and indicators is carried out and damage may be put back, replaced. The transformer oil will be replaced if the air level is degraded.
Obsolete parts must be provided otherwise the circuit breaker can be replaced. A qualified professional should diagnose and verify the fault.
If any tear, accident or electrical fault detected in switchgear and control material by experienced engineers, then repair the repair center . broken parts or replace equipment.
During troubleshooting, the engineer should check if theRelay operation meets specification or not. If a problem is reported, it is repaired, recalibrated or replaced.
A cable is an item of equipment in the electrical system. A single fault in the cable can shut down the entire system. The splice is checked and the cable is replaced immediately.
In the event of maintenance, the repair and replacement process requires financial support and reporting. Thus, legal control intervenes. It is about defining a true picture of the financial statements such as the balance sheet, the income and expenditure account, the collection and the payment. It shows the distribution of funds for repair, purchase of electrical equipment, etc.
Perimeter of SA
According to the financial management system, the perimeter includes -
Adequacy of the project financial system: efficiency of accounting, financing,control of operations, compliance with plans, policies, procedures, reliability of the accounting system, data and reports and verification of assets and liabilities.
All documents, records and accounts should be carefully kept for a project.
1. What maintenance is applicable after a failure?
a) Preventive maintenance
b) Corrective maintenance
c) Both A and B
d) None of the above
When a fault, a failure or malfunction is detected, corrective maintenance is applied to the equipment.
2. If preventive maintenance is offered monthly, it is called ______.
a) Corr maintenanceective
b) Emergency maintenance
c) Scheduled maintenance
d) Protection maintenance
An s: c
When preventive maintenance is performed over a period of time, it is called Planned maintenance.
3. Which device measures the concentration of fluid?
d) None of the above
- The barometer measures atmospheric pressure.
Electrical safety - Duties and obligations
We will now learn theThe duties and obligations of the various stakeholders related to the use of electrical equipment.
Obligations of suppliers
The relationship between a supplier and a customer is a contractual relationship. However, there are a few moral obligations the supplier has to meet to ensure customer satisfaction.
The functions of a product must meet consumer expectations.
The consumer's mind has calculated the lifespan of a device. Therefore, the product should work effectively for the expected duration.
The product must be repaired or replaced during or after a specific period of time.
It is a degree of risk associated with the product that the product must be safe under normal conditions.
If a product does not meet the expected specification or if it is a defective itemkiller, arrangements for its replacement must be made.
The type, nature, components of the product and the hazards associated with the product must be clearly specified.
A technical assistant must be on site to repair, maintain and provide good after-sales service.
The terms and conditions document including invoice, warranty, wa rranty certificates, test reports and an installation guide must be provided.
Moral obligations of the manufacturer
Note the following points related to the moral obligations of a manufacturer -
The duty must comply with the declarations of reliability, service life, maintainability and safety
Do not distort and constrain
Theory of due diligence
This is a common factnnu that a manufacturer enjoys an advantageous position than a consumer. It is therefore the responsibility of the manufacturer to take special care of the confidence and best interests of the consumer. This theory is known as the due diligence theory. According to this theory, a supplier is responsible in the following areas:
Advertising plays an essential role in establishing relationships between producers and customers. The advantages of advertising are -
- It attracts the audience
- Creates the intention to buy from a customer
- Creates a desire for the product
- Leads the customer to buy the product
Duties and obligations of a factory owner
Let 's now see the duties and obligations of a factory owner. A factory owner should review thes following items -
The factory commission project goes through the following steps -
Completion of mechanical work - Installation of piping, equipment, integrity, inspection, cold alignment, checks point-to-point continuity and preservation
Before commissioning - Cleaning, testing, blowing air and steam, rinsing , passivation, system power-up and instrument check
Commissioning - Function test, loading, operation of the equipment, electrical function test and safety test
Acceptance of the function test - A small unit operates for 12 hours continuously
Human Resource Management - After all the paper work and a successful commissioning, the owner has ae responsibility towards its employee. Management of engineers, technicians and operators is necessary for a successful start-up.
Operation of the factory
A successful factory commission consists of four parts including if one of them fails , the installation will not be considered successful.
No lost time accidents - Safety factor bothers all beginners. So, there is more stress on the design, construction and commissioning.
No Equipment Damage - This function is a matter of discipline in each section of the design, construction, operation and commissioning team in service.
About the test product: The test team should take a reasonable amount of time to complete the test of the product.
No environmental incidents - The successful completion of a test product within a period specific defines this function and guarantees the absence of environmental risks.
Healthy and Safe Environment
As other plans include inherent risk, a health, safety and security management plan The environment must be properly planned for the project. Therefore, the following procedures should be followed for each workplace.
- System identification
- Pre-start safety examinations (PSSR)
- Work authorization system
- Hazard identification and risk management
- Simultaneous operations (SIMOPS)
1. What is the acceptable time to test a product?
a) More than seven days
b) Less than seven days
c) More than fourteen days
d) Less than fourteen days
The test engineer must specify the time required to test the product.
- Less than two days is considered very good
- Seven days is acceptable
- More than fourteen days is less than acceptable
2. Which section does the theory of due diligence not focus on?
According to the theory of due diligence, a supplier has responsibility in the areas of design, productionand information.
3. Which of the following is not a component of the HSE management system?
a) System identification
b) Safety before start-up Notice (PSSR)
c) Pre-commissioning to the working system
d) Work authorization system
The components of health security and environmental management The system is
- Identification of the system
- Pre-start safety examinations (PSSR)
- Authorization to work on the system
- Hazard identification and risk management and simultaneous operations (SIMOPS)
Electrical Safety - Primary Ex Protection
Hazards are usually created in chemical factories, raFineries and paint shops, cleaning equipment, mills and stores for crushed products and in tank installations and loading areas for flammable gases, liquids and solids. Explosion protection defines health and safety in the workplace.
The principle of explosion protection
When a mixture occurs in air under atmospheric conditions with flammable substances in the form of gas, steam, dust, fibers or flywheels, an explosion hits the workspace. The security setting is a function of pressure, temperature and oxygen. Limitations are therefore necessary. There are three blast factors.
- flammable material
- Oxygen (air)
- Ignition source
Figure 1: Explosion base
By limiting any of the above factors, the probability of a primary explosion can be reduced and protection can be determined accordingly.
Basic / Primary Explosion Protection
Primary explosion protection is a process of reducing the number of flammable substances or atmospheric oxygen to a point that does not ensures no risk of explosion. Open layout and adequate ventilation increase air circulation and flush air. It is not possible to completely replace the atmospheric oxygen in an area where people are working. According to the analytical facts, there are three possibilities of explosion in the presence of flammable gas.
Due to heat - open flame / hot surface / hot gases
Electric sparks - opening and closing of contacts, short circuit, static discharge
Mechanical spark - friction,hammering, grinding
The first question arises: is there any form of hazardous material that can potentially cause an explosion. So what is the quantity of these combustible substances? The explosion potential of an atmosphere must be measured. The implementation and compliance of the ex-primary protection must comply with the rules and standards of the ex-protection.
Primary protective measures against ex
The main objective of ex-primary protection is to avoid hazardous substances. Protective measures are only intended to reduce the probability of occurrence of such materials and their spreadability. The measures must be cost-effective. Some of the protective measures are below -
Try to use non-combustible or less volatile substances or replace critical components if possible.
The parts of the system must becan be used with inert gases such as nitrogen.
Dilute combustible liquids with a non-reactive material such as water.
Reduce the number of combustible substances.
Humidification of dust is necessary.
Regular cleaning also reduces the amount of dust.
Use enclosures filled with inert substances
Provide natural or artificial ventilation for systems that limit the concentration of flammable materials .
Install a hazardous gas detection system that can provide notification via an alarm or system interrupt.
The flash point of flammable liquid should be changed by adding other materials such as water. Otherwise, the processing temperature must be lowered. If the flash point of a flammable liquid is higher than the working temperatureIn this way, faults, stoppages and leaks are checked.
1. Which one is not a blast factor?
B. Electric spark
D. None of these
Explanation - No fire exists without oxygen in the 'air. An electric spark is a source of ignition and acetylene is a flammable substance. So A, B and C are the factors of the explosion.
2. Why is ventilation necessary for every workplace?
Explanation - All ( A, B, C) are related to each other which are the works of a ventilator. Ventilation is necessary for a workplace to circulate and flush the air which reduces the concentration of combustible substances.
3. What substances are used in the pens?
B. Inert gases
C. Alkaline materials
D. All of the above
Explanation - Inert gases do not react with any Material. The housings are therefore protected by inert gases.
Electrical safety - Secondary Ex protection
If the electrical equipment was kept under explosion protection, that doesn't necessarily mean it would be a fully-fledged unit.t sealed or encapsulated.
Types of protection techniques
There are seven known types of protection techniques. Let's take a look at the different techniques -
Type M or Type h (hermetically sealed)
This is a design where the equipment is stored in a completely sealed environment. Parts that can eventually ignite gas or vapor upon exposure to the atmosphere are hermetically sealed with resin. It is suitable for zones 0, 1 and 2. Usually, small compressors, miniature motors and small lamps benefit from this type of protection system.
Type q (filled with sand or powder)
Here an enclosure is filled with quartz sand of Size 1.6 mm having a weight of 0.1% d 'water. Electrical equipment is placed inside it. When an arc occurs indoors due to inflammation, it is absorbed by the sand itself. It ismainly used for fuse banks and capacitors. It is suitable for zones 1 and 2.
Type O (oil immersion)
It is similar to type q with very little difference; here the sand is replaced by mineral oil. The pregnant shows high and low oil level on her body. It is used for c circuit breakers, transformers and switching units. Zones in Zone 2 go through a similar security procedure.
Type P (pressure vessel)
In this case, the chamber is pressurized with a gas whose value is greater than atmospheric pressure. Thus, the equipment present inside remains protected from external gases and vapors. The process is called the gas purge technique. It is used for zone 1 and zone 2.
Type I (intrinsically safe)
Unlike the zones above, this is not an enclosure; it is more of a circuit design. The conceptis to limit the input of current and voltage into the ignition energy necessary to ignite flammable gases / vapors or air mixtures under normal or anticipated fault conditions. It is used for zone 0, 1 and 2.
Type e (increased security design)
This security scheme is only for zone 2 zones. Here , the enclosure designed is generally of cast l or molded polypropylene or fabricated sheet l. The size of the enclosure is decided in such a way that the surface temperature can be limited within the intended temperature class.
Type d (explosion-proof or explosion-proof design)
This is a very popular technique. The zones of zone 1 generally pass through such a security system. Here, the material to be protected is kept inside a CI or LM-6 type cast l. Sometimes a reinforced polypropylene casing molded in GRP is also used. Precautionsare taken to prevent the occurrence of explosions. Even if this happens, it will turn off while moving inside.
Precautions against highly flammable contents
In an industry, the presence of highly flammable materials increases the risk of danger to its container (structure) and to people working nearby. Events can become more dangerous if the structure is struck by lightning. That's the reason; for these areas a higher level of security and protection must be followed.
If a structure contains highly flammable solids, liquids or gases. pour then consider the following recommendations -
Use an all-l structure for storage of flammable materials
Keep flammable liquid or gas inside a fully-flammable structure. llic. In case the degree of danger is high, it is better to opt for a strgas-tight ucture.
Close all openings in the structure
Sometimes, due to lack of inspection, a small opening in the gas or steam chamber causes problems. He directs the lightning flames to get inside, causing an explosion. It is therefore strongly recommended to seal these openings.
Regular maintenance of containers
It is the duty of the safety inspector to put the containers for daily / weekly checks. Careful monitoring will make faults public beforehand and the safety officer can take appropriate action to avoid possible dangerous consequences.
Avoid the accumulation of flammable air-vapor mixtures around these structures
Lightning flames can easily charge flammable air vapor particles and can pass through them up to 'at their source. In this regard, it is important to keep the mixture air-vapor of these structures removed from contact with lightning by any means.
Reduce spark gaps between l conductors
Inside the structure, there may be conductors with a gap between them. In due time, the accumulation of flammable air or vapors inside these spaces can create a hazardous situation in the event of exposure to lightning. In a lightning strike, flammable air or vapors transform into charged particles and can eventually cause sparks between the conductors. Thus, during a regular safety check, it is necessary to reduce the spark gaps.
Location of the structure
Some places are prone to lightning and if the structure is present in such areas then it is likely to be struck by lightning from time in time. Here the main duty is to move the structure from this location to another location, more immune to cobetween lightning, almost immediately. Othe Otherwise, it will cause catastrophic dangers not only for the instruments present inside but also for the personnel working nearby.
Create multiple protection zones
This is consistent with the point we discussed just before. If the structure is not able to be transferred from the position of a very exposed lightning zone, it is important to create several protection zones around the structure. Lightning must pass through a number of protective layers before reaching the structure.
Safety measures when handling lighting protection equipment
For buildings containing highly flammable liquids or gases, it is important to protect them from lightning . However, handling lightning protection equipment is no easy task. A single mistake can lead to seriousdangers for the structure and people working nearby. Depending on the type of building to which the lightning protection equipment has been incorporated, there are different handling methodologies. Let's understand what the methodologies are.
Building at risk of explosive dust or flammable vapors
For this type of building, it is recommended to add an integrated lightning protection system. It should have vertical air terminals and horizontal air terminals. Depending on the type of storage inside the building, the height of the vertical terminals should be set at least 1.5 meters while the horizontal air terminals should be spaced 3 to 7.5 meters from each other. other.
Explosives storage building and workshops explosives
Here it is necessary to add fully assembled systems. The vertical and horizontal spacing in this case should be 0.3 m d respectivelye high and 7.5 m apart.
Small explosives storage buildings
Buildings of this type are very unlikely to be struck by lightning. Integrated mounted systems are not required here. Only a vertical pole type lightning protection system can do wonders.
Storage of explosives in buildings
Some buildings contain explosives such as nitroglycerin (NG). These structures require overhead horizontal air terminations as fully mounted systems and vertical post types will not be able to provide the desired protection. These suspended horizontal air terminations must be placed at a minimum height of 2 m above the structure. About the internal spacing, it should be at least 3m between the terminations.
Electrical safety - Earthing
A fault current always looks for the path of low rresistance and through that travels to neighboring systems thus damaging them to the heart. In this regard, all the main elements of the l structure should be linked and well connected in accordance with the lightning protection system. This includes continuous l reinforcement and the services of the relevant l structure.
Such a connection must be made at least in two places around the structure. They must be equidistant and the distance between them must not exceed 15 m. The structures contain ironwork frames. Metal frames must also be glued to the lightning protection system.
All conductors entering inside must be l cased. L The l enclosure must be electrically continuous within the structure It is the responsibility of the safety officer to inspect the structure.
The point at which the conductor marks its entry inside the structure must be earthed with respect to the supply side and must be connected directly to the lightning protection system.
There is a different connection strategy concerning the conductors of the structure connected directly to the overhead lines. Here, a buried l sheath armor cable should be connected between the overhead line and the entry point of the structure.
Surge protection devices such as re sistors can also be connected. The earth terminal of this protection device must be connected to the cable sheath or to the armature. A bond of this type will protect the entire structure from lightning.
Electrical safety - Safety of transformers
Transformers are a major source of electrical power for any industry.
Conversion of voltage levelcan cause serious damage to a person or the surrounding area if it is not subjected to strict protection measures. It is the duty of the safety inspector to perform the following condition assessments on the transformer with the following checklist -
Main transformer inspection checklist
| Task|| Yes || No || N / A || Comments |
| Main tank || || || || |
| Paint System in good condition || || || || |
| Rust observed || || || || |
| Grounding of the tank in good condition || || || || |
| Secure conduits and fittings || || || || |
| External central floor provider || || || || |
| Oil leak observed || || || |
| Cooling system || || || || |
| Radiator or cooler fins cleaned || || || || |
| All v opens and secures the main tank || || || || |
| All fins in place and operational || || || || |
| All oil pumps in place and operational || || || || |
| Function of oil flow indicators correctly || || || || |
| Vibration or excessive noise observed || || || || |
| Oil leak if any || || || || |
| Oil preservation n || || || || |
| Positive pressure of inert gas || || || || |
| Correct setting of the blanket nitrogen regulator || || || || |
| Correct check of gas blanket pressure || || || || |
| Crossing || || || || |
| Everything is clean and no flaws || || || || |
| Correct check of oil levels || || || || |
| Oil leak if any || || || || |
| De-energized tap-changer (DETC) || || || || |
| Location of the tap position indicator || |
| Locking mechanism verified || || || || |
| Load tap changer (LTC) || || || |
| Location of the station ind icator tap || || || || |
| Silica gel breather || || || || |
| Oil leak if any || || || |
| Control cabinet || || || || |
| Connections / components in good condition || || || || |
| Gaskets checked || || || || |
| Heater strip verified || || || || |
| Protective devices || || || || |
| Reading the oil temperature indicator || || || || |
| Set points of the temperature indicatoroil || || || || |
| Reading the indicator winding temperature || || || || |
| L set points 'winding temperature indicator || || || || |
| Alarm / Buchholtz relay trip || || || || |
| Alarm / trip of gas detector || || || || |
Electrical safety - Safe handling of engines
Today, the majority of unintentional injuries are caused by traffic accidents. Users of equipment in a high-energy environment suffer from serious risks, when effective precautions are not taken. Given the multitude of risks involved, it is important that users apply and adhere to security practices. There are
Safety for single phase motors
Single phase motors include all devices whose output power is about 1 horse power (1HP). Single-phase motor is widely used for household applications such as washing machines, electric toys, fans, blowers, among other devices. In order to ensure the safety of these devices, it is important to take the following precautions -
Constant troubleshooting to determine if the functionality of the face single engines are working properly.
Perform a proper motor winding inspection.
Perform un Power test to determine if there is a problem with the motor.
Do not leave a shorted battery for a long time as it will eventually explode.
Do not power motors above 12 volts.
Safety for 2-phase motors
Before starting to work on 2-phase motors, make sure you follow all the safety instructions of based. Failure to follow safety precautions often results in injury such as shock, fire, or personal injury. Some of the safety precautions are as follows -
Persons not familiar with the operation must I am not authorized to access areas work where two-phase motors operate.
Remember to always wear glasses to keep your eyes safe.
Never let an engine run unattendedspear.
Safety of three-phase motors
Three-phase motors include heavy industrial machines. Machines require high voltage to run them, which is why extreme measures must be taken to avoid accidental injuries which can be of a dangerous nature. Before using these machines, be sure to wear safety equipment such as gloves, boots, and ear masks to protect yourself from the harmful effects. the person who works there. Therefore, the security manager must be extremely careful. Motor users must wear all the necessary safety equipment to avoid any faults. Following these measures helps to detect anomalies.
Electrical safety - Safe handling of generators
Back-up generators are necessary to fight against power outages. They are practical and easyare to be used but can be dangerous to life and property. It is important to follow proper standards, procedures and precautions when installing, operating and maintaining electrical generators. It is recommended that you create a safe working environment by consulting the manufacturer, reading the manuals and following the guidelines. Safety practices not only avoid hazards, but also increase the quality and life of the equipment.
Safety precautions during installation and maintenance
Safety of generators depends on several sections from selection to maintenance. Any error can lead to serious danger.
Selection of a generator
The selection depends on the number of devices to be switched on in the event of a power failure. Depending on the constant power demanded and the overvoltage, the generator is selected.
In Processtabilization support
Authorized, qualified and certified technicians and engineers who have knowledge of generators, safety codes and standards should be employed. The installation process must meet the NFPA 110 information on "Standards for Uninterruptible and Uninterruptible Power Systems".
In operating condition, the generator evacuates fumes (toxic gases such as carbon monoxide). be properly ventilated. The area must be free of any combustible material.
Regular inspection and periodic maintenance of generator parts, cable connections and batteries are required. The air intake system, fuel system, exhaust system, electrical systems and control system should be checked on a schedule. If any damage is found, replace it immediately.
InspeGenerator ction for safety
Routine inspection can reduce the occurrence of hazards. For diesel generator sets, exhaust gases, fuel, engine and DC electrical system should be closely monitored.
Lubrication service - The level and quality of the oil should be checked using 'a gauge at regular intervals.
Cooling system - The coolant level is checked. The radiator is cleaned without damaging the fins.
Fuel System - Store fuel before it degrades. Testing and polishing are also major requirements. The air cooler hose and hoses should be checked for leaks, holes, cracks, dirt and debris.
Battery test - Battery testing and cleaning is bornnecessary to provide adequate starting power. The terminals are washed with the baking soda and water solution and smeared with petroleum jelly. Density and electrolyte level are checked. If the hydrometer reads less than 1.215, charge the battery. If the electrolyte level is low, fill the filler neck with distilled water.
Motor exercise - Motor exercise should be performed at least once a month for 30 minutes between loading and starting. 'unloaded state. The engine should be clean all the time.
Exhaust System - All connection points, welds and joints are recommended to be properly checked for any leaks and should be repaired immediately .
1. What standards must be observed for the installation of the generator?
a) NFPA 70
b) NFPA 85
c) NFPA 110
d) NFPA 100
NFPA 110 describes "Standards for Uninterruptible Power Systems and backup ”, which includes the process of installing the generator.
2. What gas is vented by the working generator?
c) Carbon monoxide
d) All of the above
In operating condition, the generator releases toxic gases such as carbon monoxide.
3. At what point of specific gravity of the electrolyte does the battery need to charge?
a) less than 1,215
b) more than 1,215
c) equal to 1.215
d) None of the above
The battery must be recharged, when the density of the electrolyte is less than 1.215. This is measured by a hydrometer.
Electrical safety - Safe handling of cranes
Loads can be lifted, lowered or moved using the crane and its foundation. This is a risky task for an operator. 'There is any type of failure, such as structural failure, overturning, collapse, loose contacts or falling objects, it may damage the load, other equipment and workers. risks, OSHA standards describe the procedure for safe handling of loads with cranes. It also covers equipment safety and the responsibilities of a crane operator for the safe use of the crane.nip the load, the crane system should be checked thoroughly.
Safety check before use
It is always recommended to take precautions to avoid dangers. Inspection guarantees the safety of the crane by vividly testing it.
The workspace should be a large area and a registered crane is used to handle the material.
The operator must be well qualified, certified and authorized to use cranes.
Workplace factors such as bearing capacity on the ground, wet or windy climate are considered for the safety of the crane.
Installation and commissioning activities should be supervised by an expert.
The components must be assembled in the correct order, including a limit switch, load indicator, sling connection, ropes and cables. 'other accessories.
If there is a faulty system, replace it immediately.
Check the crane for oil, vibration, or noise leaks.
Familiarize yourself with the controller.
Check indicators such as load indicator, working space limiter, anti-collision device and crane movement indicator .
Check the hook and make sure it is in good working condition
Check the wire rope for any deformation such as broken wire, strand distortion, kinks, excessive wear, bird caging, crushing, rusting and stretching.
Make sure the sling angle is always greater than 45 °
The operator should take into account the following safety concerns and avoid accidents when using the crane and thehoist.
| Sr.No. || Deio n || Examples |
| 1 || There are no new dangers in the environment of 'exploitation. || |
| 2 || Assumptions and doubts lead to accidents. || |
| 3 || The crane should take the load from the center and not from the side. load balancing || |
| 4 || Don 't solift the load on people || |
| 5 || Do not pull on the lifting cable or chain like a sling || |
| 6 || Do not try to to be multitasking || |
| 7 || Make sure the load is properly connected and communicating clearly with other team members || |
| 8 || Make sure the clearance between cranes and fixed objects. A ≥ 750 mm and B ≥ 600 mm || |
| 9 || Do not leave the suspended load unattended || |
Emergency plans should be prepared at the time installation for each workplace where the crane will operate.
There should be an entry and exit facility for the crane. 'emergency of a crane.
The emergency plan should be tested for its effective response and the same should be notified to the emergency services.
Training in emergency procedures should be provided to workers.
A medical facility should be available near the area of operation.
Evacuation location signs should be placed in a location where workers can see everything in the workplace.
1. What is the angle of the sling for safety reasons?
a) less than 45ᵒ
b) more than 45ᵒ
c) less than 60ᵒ
d) more than 60ᵒ
If the sling angle is greater than 45ᵒ, then the load will be lifted correctly parallel to the horizontal surface. If the angle differs, the load will be tilted and may cause danger.
2. What is the safety distance between the crane and the load?
a) ≥ 750mm
b) ≤ 750 mm
c) = 750mm
d) None of the above
For safety reasons, the calculated key The space between the crane and the load is more than 750 mmr.
3. What happens when the crane lifts the load on one side?
a) the load will be tilted
b) the load will oscillate
c) load may drop
d) All of the above
If the crane lifts a load on one side, the load tilts, swings or falls. This can lead to dangers. It is therefore recommended to lift the load in its center.
Measures during preventive maintenance
If the installation and its accessories are not inspected and maintained regularly, they end up becoming dangerous for workers working with or around it. 'them. Machines can break down causing loss of business. Therefore, to avoid such accidents, periodic maintenance coupled with a safety check is essential. Now, acquiring the knowledge about periodic maintenance is not enough, it is also important to know the safety measures to be followed when performing preventive maintenance on site.
Safety measures for preventive maintenance
Let us now see the different safety measures for preventive maintenance.
No safety inspections and maintenance should be carried out without protective equipment. For example, gloves, masks, goggles, boots, jackets, etc.
Pass around a work permit
If you are going to service a crane offline, issue a work permit and circulate the message among the workers. Otherwise, due to lack of knowledge, the person working on the equipment may encounter a risk.
Perform a risk assessment
Beforecarry out maintenance activities, a risk assessment must be carried out and all workers must be involved in it. This will help workers better understand the process and allow them to conduct their own additional risk assessment.
Efficient and continuous communication
Most of the time, it is the half-broken information chain that causes incidents during preventive maintenance. As stated earlier, every employee of the company should be informed of the ongoing preventive maintenance at least 3 days in advance. In addition, the safety officer should consider letting workers notify this on the day of maintenance as well.
Preventive maintenance is subjected to test a machine at its maximum capacity. Therefore, it should not be compromised just because you don't have the right tool. GatherProvide the tools, cables, testers, and other equipment necessary to perform the test without exposing yourself to high voltages and currents.
Always have someone to watch your back
It is always good practice to do preventive maintenance work in groups of two or three. When you work as an individual the risk factor increases. However, when you have someone to watch your back, the risk factor tends to be low.
Electrical Safety - Types of Safety Equipment
Risks of Occurrence of Hazards in the Workplace Cannot be ignored. Thus, every employee should be provided with adequate personal protective equipment (PPE) in accordance with Article 19 of the Constitutional Law of 1984 on Safety and Health.
Categories of personal protective equipment
Personal protective equipment can be consideredin the following different categories.
Chemicals, dust can get inside the body through breathing, causing chest pain, headache and other symptoms related to respiratory problems. Therefore, respiratory safety equipment such as a disposable filtering half mask, half mask, full face mask, etc. is necessary.
The following equipment is used to protect the eyes -
- Safety glasses
- Eye shields
- Face shields, etc.
Hearing protection equipment is necessary to protect the eardrums if the noise or sound level exceeds 85 decibels. For protection, equipment such as earplugs, semi-inserted earplugs and earmuffs can be used.
Harmful chemicals and substances can be absorbed through the skin, causing bruising, cuts, abrasion, etc. To avoid this, hand safety equipment can be used such as gloves, finger guards and arm guards.
In plant areas, falling from height, rolling, crushing or penetrating sharp materials are more common. To protect the foot from all of this, employees need the following -
- Safety shoe for the toes
- Metatarsal protectors
- Toe protectors
- Studded steps, etc.
Protecting employees from potential head injuries is the primary part of any safety program. Therefore, employees are provided with hard hats. The helmets are
- Class A (Vol res up to 2.2 kV)
- Class B (Vol res up to at 20k volt)
- Class C (provides protection against light weight)
Implications of human behavior
The role of a being human in the workplace is of great importance. No matter how technologically equipped an organization is, it will always need a human to operate and monitor. The safety of a worker lies in his approach to a machine. Careless behavior when operating a machine leads to accidents and even death in some cases. It is quite important to analyze the behavior of a worker towards the machine in order to be able to stop any electrical hazard in the future.
Identification of the accident
In this section we will see how to identify an accident. The following points should be taken into account foridentify an accident -
Cause of the accident
Identify the reason that led to the accident.
A detailed analysis of the chain of events, which led to the accident.
Difference between accidents
Comparison of the current accident with previous accidents.
The intensity of the risk
Identify the risk associated with the task that is performed by the workers.
The fault of the organization
Determine if it is the fault of the worker or the organization.
In this section we will learn how to improve the system.
Each job requires a different set of actions and each action of one worker has a knock-on effect on the other. Each task performed by a worker requires a certain degree of choice on the part of the worker and this choice can sometimes lead to risk.s in the workplace.
Follow the example below to get a fair idea of task analysis.
Suppose a worker at a workplace is asked to increase the temperature of the air conditioner by 2 degrees. Now, this task seems easy to perform, but errors can occur due to human behavior. Consider the following actions which can cause errors -
Pressing the wrong button
A slip type error will occur if the worker does not know which button to press and presses the wrong button assuming it is right.
Run without knowledge
The worker presses the right button, but meanwhile he / she thought (guessed by himself) that the switch was for some other use.
In this situation, the employee knows exactly which button to press but always presses the wrong button to finishthe task earlier.
All humans have a tendency to make mistakes in the workplace, especially at the end of their shift, because they are tired and focus on reach their homes as soon as possible. Therefore, while evaluating human behavior and performance, it should be taken into account that no human is 100% perfect. When a worker is faced with stress inside or outside of work, they are most likely to make a mistake. Addressing the Problems can help prevent errors and prevent future accidents.
The analysis of a worker 's choice is classified into two perspectives -
Personal point of view of the worker
- Personal characteristics
- The way of learning
- The tendency to take risks
Work perspectivetheir in the workplace
- Organizational culture
- Office policy
- Organizational reward system
- Management system
- Quality of training provided by the organization
Classification of human errors
In In this section, we will classify the different human errors.
There are two types of classification approach -
- PHECA - Analysis of potential causes of human errors
- SHERPA - Systematic approach to reducing and predicting human errors
L ' analysis of potential causes of human error focuses on the given tasks in w orkplace and the error he / she makes. The tasks can relate to operation, maintenance, monitoring, verification and communication.
Here are the errors caused by workers -
- Task not completed
- Partially completed task
- Completed task but not precisely what was requested
- Completed the task more than what was requested
- Completed the task before the specified time
The systematic approach of human error reduction and prediction combines task and error methods. The approach stores the type of error separately. SHERPA links a worker 's mistakes to their performance goal. The causes of the error are related to the competence of the worker or to the knowledge he possesses.
1. Identifying the accident in an organization is crucial. Which is not a method of identifying a work accident?
a) Cause of accident
b) Leading events to a crash ent
c) Nume of people involved in the accident
Ans - c
2. Which of these elements does not relate to the "personal point of view of 'a worker' when analyzing choices?
a) Personal characteristics
b) Reward system
c) The tendency to take a risk
Ans - b
3. What does PHECA mean?
a) Analysis of potential causes of human error
b) Awareness of the potential cause of human error
c) Awareness of the cause of personal human error
Ans - a
Dos and Don'ts at a Glance
The confusion between energized equipment and dead is one of the main reasons that could lead to an electrical accident. It is essential for an organisation to properly train its workers to take appropriate precautions when using machines. However, it is also the responsibility of a worker to work with extreme caution and to refrain as much as possible from hazardous situations.
What to do for a worker
In this section, we will learn about the actions that should be performed by a worker.
Before performing a task, make sure that the equipment is 100% dead and is not in working order. energize yourself at any stage of the work.
To be on the safe side, it is ideal to write down any actions you are going to take on a control sheet.
Re-analyze your written instructions, and if possible, you can discuss them with your supervisor or colleagues.
Always follow the work instructions provided to you.
Use of a well rated instrument is required. It is recommended that only good quality insulated tools, probes and prods be used.
Working in sequence is the key to safe operation, especially switching sequences. Make sure you turn off the isolator first and then turn off the associated breaker.
When testing equipment, it is essential to create a spacious exclusion zone.
When working in the field, it is your life that is at stake. So you must take proper precautions when working. Before taking a risk, it is always advisable to think about the repercussion and take the appropriate measures.
If you find that someone is interfering with the way you work, politely stop them. If a coworker is working on your testing area and is following the wrong procedure, insist that he is following the correct method.
Before you start your job, make sure that you write up an appropriate layout of all your equipment in the correct order. Following a correct order will not only help you provide a comfortable working posture, but also give you other benefits such as -
Provide ample workspace
Makes your equipment easy to access
Gives you time and visibility needed to read your instructions
Provide adequate light
Provide you with a quick gateway in case of urgency
Things not to do for a worker
In this section, we will see the different actions that should be avoided by a worker.
Never try to close a circuit during a fault, while it is still being processed. A fault must alwaysbe located, then it should be removed or corrected. Until the proper steps have been taken, do nothing with the circuit.
Unless the load to the engine has been disconnected, do not try to turn on the power to the generator set.
If the primary winding is able to pass current, never try to open the secondary winding. Never use the open circuit of the secondary winding as an energizer for the primary winding.
Before working on a circuit make sure that it is completely dead or has been thrown out by an authorized worker. Until then, it is best to stay away from it.
When using test equipment, never try to interact with safety devices as this is quite dangerous.
When running a zdc machine, it is crucial to make sure that youlay out an armature and open the field circuit at the same time. Without proper arrangements, never try to run a DC machine. However, you can only try it with caution if you secure the breaker in the field circuit.
When using test equipment, never change, permanent connections and even if you do, be sure to consult your supervisor properly . If you modify test equipment, be sure to label it with an uppercase letter. After using the equipment, return the connection to its original position unless your supervisor has instructed you not to do so.
Never use damaged equipment and never leave faulty equipment in a place accessible to others.
Even if your injuries appear mild, always have you adequately checked by a qualified expert.é.
1. What should not be done before using equipment?
a) Modify the permanent connection
b) TO energize it with adequately
Ans - A
2. When running a DC machine, you should
a) Open the field circuit
b) Close the field circuit
Years - A
3. What should be written on a control sheet?
a) The correct action to take when performing a task
b) Technical specifications of the equipment
Ans - A