ELECTRICAL WORKSHOP PRACTICE AND TECHNOLOGY
CTE 112
ELECTRICAL SAFETY
Electricity can kill or severely injure people and cause property damage.
However, you can take simple precautions when working with or near electricity and electrical
equipment to significantly reduce the risk of injury to you, your workers and others around
you.
An Electrical Hazard can be defined as a serious workplace hazard that exposes workers
to burns, electrocution, shock, arc flash/arc blast, fire, or explosions. By identifying these
hazards, and understanding how they happen, we can take steps to protect ourselves.
The main electrical hazards
The main hazards of working with electricity are:

electric shock and burns from contact with live parts

injury from exposure to arcing (when electricity jumps from one circuit to another)

fire from faulty electrical equipment or installations

explosion caused by unsuitable electrical apparatus

static electricity igniting flammable vapours or dusts, for example in a spray-paint booth
Electric shocks can also lead to other types of injury, for example by causing a fall when
working from ladders or scaffolds etc.
Even incorrectly wiring a plug can be dangerous and lead to fatal accidents or fires.
Some common causes of electrical and electronics hazards include:

Overhead power lines
These carry high voltages and can cause severe burns, electrocution, or death. Keep a
minimum distance of 10 feet away from them.

Overloaded circuits
Too many devices plugged into a single outlet can overload a circuit. Circuit breakers are
designed to shut down the circuit in this event.

Faulty wiring
Damaged or exposed wiring can cause electrocution and power surges.

Damaged insulation
Damaged insulation can cause fires, shocks, and burns. Turn off the power and replace the
damaged insulation.

Damaged tools and equipment
Inspect power tools before using them for damage like dents, frayed cords, or water
intrusion.

Wet conditions
Water can conduct electricity, so using electrical equipment in wet conditions can lead to
electrocution or fires.

Exposed electrical parts
Exposed electrical connections can be hazardous.

Improper grounding
Improper grounding can create a lethal hazard. Correct grounding is essential for the safety
and proper operation of electrical equipment.
Other causes of electrical accidents include:

Unsafe work systems

Inadequate information

No training

Inadequate isolation

Unsafe rules

Poor control of work activities

Live working

Unsuitable test equipment

Poor maintenance

Failure to manage work
Prevention of Electrical Hazards
To prevent electrical hazards, it is necessary to use electrical safety systems and devices such
as a three-wire system, Ground Fault Circuit Interrupter (GFCI), circuit breakers, and fuses.
A good method of preventing electrical hazards is to use electrical safety systems and devices
that are designed to prevent both thermal and shock hazards. For one, the use of a three-wire
system can help guard against these hazards by using live or hot, neutral, and ground wires,
with the neutral wire and case of the appliance grounded. Another way is by using a Ground
Fault Circuit Interrupter (GFCI) which functions to prevent shock by detecting the loss of
current to unintentional paths. It is also crucial to employ circuit breakers and fuses which work
to interrupt excessive currents to prevent thermal hazards such as overheating and potential
fires.
Regular Inspections: Conduct routine inspections of electrical equipment and wiring to
identify and address any issues.
Qualified Professionals: Hire qualified electricians for installation and maintenance work.
Avoid electrical work unless you have the necessary expertise.
Avoid Overloading Circuits: Do not overload electrical outlets or circuits. Use power strips
and extension cords responsibly.
Ground Fault Circuit Interrupters (GFCIs): Install GFCIs in areas where water and
electricity may come into contact, such as kitchens and bathrooms.
Electrical Safety Training: Provide electrical safety training for individuals working with or
around electricity.
Considerations and Rules Concerning Health, Safety and Environment at Electrical
Workplace in Nigeria
Here are some health, safety, and environmental considerations and rules for electrical
workplaces:
Overhead power lines
Maintain a minimum distance of 10 feet from overhead power lines and nearby equipment.
Frayed, loose, or exposed electrical cables
Frayed or cracked cables can expose live wires, which can lead to electrical fires or electric
shock.
Improper grounding
Improper grounding increases the risk of electrocution.
Keep electrical equipment away from water
Water and electricity are dangerous when mixed, and can cause serious damage to appliances
or electrocution.
Restrict access
Make sure that de-energized electrical equipment and circuits are locked out, and don't allow
access to areas where energized equipment is being worked on.
Unplug equipment safely
Gently pull the equipment by the plug instead of jerking the electrical cord.
Use and maintain tools properly
Use proper wiring and connectors, and wear correct PPE.
Unqualified personnel
Unqualified personnel should not interact or come close to electrical currents greater than 50V.
Maintain a safe distance
If you must work in the same area or room as an electrical hazard, maintain a safe distance.
Both Employers and Employees should: Ensure that the way work is done is safe and does not
affect employees' health. Ensure that tools, equipment and machinery are safe and are kept
safe. Ensure that ways of storing, transporting or working with dangerous substances is safe
and does not damage employees' health.
Earth Continuity Conductor
An earth continuity conductor (ECC) is a wire that connects the metallic parts of an electrical
installation to the earthing lead
The ECC connects the metallic parts of an electrical installation, such as the metallic
framework, motors, generators, transformers, switch-fuses, distribution boards, and more
The ECC can be a metal conduit, cable metallic sheath, flexible wire, or special continuity
conductor
The ECC has a low resistance and joins all the metallic parts of the installation network together
IEEE rules
According to IEEE rules, the resistance between the consumer earth terminal and the ECC
should not be greater than 1 Ω
Earth continuity devices, such as current leakage testers, are used to test the safety of electronic
instruments and appliances.
Earth electrode means a metal rod or rods, a system of underground metal pipes or other
conducting object, providing an effective connection with the general mass of the earth.
An earth electrode is a conductive material that's buried in the ground to connect an electrical
system to the earth and protect people from electric shock and electrocution.
Earth electrodes are a vital part of electrical systems and are used for earthing, also known as
grounding. They work by providing a safe path for fault currents to flow to the earth, diverting
excess electricity away from people and equipment.
Earth electrodes can be made from a variety of materials, including: Copper conductor, Cast
iron plates, Steel piles, Copper-bonded steel rods, and Concrete-encased electrodes.
Earth electrodes should be buried at a depth of at least 0.8 meters to ensure they are sufficiently
soaked and to account for frost depth in the winter.
A consumer's earthing terminal is a connection point in an electrical system that connects
the consumer's equipment to the earth or grounding electrode system. Earth terminals are
important for safety and functionality, and they serve several purposes in electrical
installations, including:
Grounding and earthing
Earth terminals provide a low-resistance connection between electrical equipment and the
earth, which helps prevent electrical shocks and equipment damage.
Bonding
Earth terminals connect metallic components and structures within a building to ensure they
are all at the same electrical potential. This reduces the risk of electrical hazards.
Protection
Earth terminals help protect electrical systems and equipment by ensuring that fault currents
are safely discharged, which prevents overheating and damage.
Earthing must be done in all buildings, and it should be by country standards and the Institute
of Electrical and Electronics Engineers (IEEE).
The Neccesity For Earthing
Earthing is a critical safety measure in electrical systems that protects people and equipment
from electrical hazards. It's necessary for a number of reasons, including:
Preventing electrocution: Earthing provides a low resistance path for electrical currents to
flow to the ground, which prevents faulty electrical systems from causing electrocution.
Preventing fires: Earthing protects against fires that may occur from current leakage.
Protecting equipment: Earthing protects electrical appliances and devices from excessive
electric current.
Stabilizing voltage: Earthing helps distribute power properly, preventing circuits from
becoming overloaded and blowing.
Lightning protection: Earthing systems are an essential part of lightning and surge protection
systems.
EMI control: Earthing is necessary to control electromagnetic interference (EMI).
Relevant Regulations Concerning Earthing
There are several regulations and standards that apply to earthing, including:
Electricity Safety, Quality and Continuity Regulations 2002: Requires that generators and
distributors ensure their networks don't become disconnected from earth in the event of a fault
Electricity at Work Regulations 1989: Contains requirements for earthing
Management of Health and Safety at Work Regulations 1999: Contains requirements for
earthing
EA TS 41-24, BS EN 50522, and BS 7430: Earthing systems should comply with these
standards
BS 7671: Provides methods for sizing protective conductors, including earthing conductors
AS/NZS5139:2019: Determines the voltage levels within an installation, which in turn
determines the requirements for earthing and insulation
IEC 62305: Provides requirements for the construction and dimensioning of earth termination
system elements
EN 50164: Provides requirements for the construction and dimensioning of earth termination
system elements
IEEE Standard 142: States that the purpose of a grounding system is to limit the amount of
voltage to the earth to within the allowed limits
Some best practices for earthing include:
Ensuring that all metallic parts of an electrical installation are bonded to the earthing system
Regularly testing and maintaining the earthing system
Using copper-clad steel for underground rods and grounding grids
Protection Of Installation By Fuse
A fuse protects an electrical installation by interrupting the flow of electricity when it exceeds
a certain level. This is done by melting or breaking a sacrificial element within the fuse, which
prevents damage to the connected devices.
Fuses are one of the primary ways to protect electrical equipment and wiring from faults. They
should be used to protect every connection in a system.
Circuit breakers are another way to protect electrical installations, and are often used instead
of fuses when it's economically sensible. Circuit breakers don't get destroyed during overload
conditions like fuses do
A fuse is a metal wire or strip that melts when the current flowing through it exceeds a certain
value. The melting of the fuse breaks the circuit and stops the flow of electricity. This prevents
the fault from causing further damage or injury. Fuses are usually placed in series with the load
or the branch circuit that they protect. Fuses have different ratings, such as voltage, current,
and interrupting capacity, that determine their suitability for different applications.
To select the right fuse for your power system, you need to consider several factors, such as
the type of load, the operating conditions, the fault level, and the coordination with other
protective devices. You should choose a fuse that can handle the normal operating current of
the load, but also interrupt the fault current before it reaches a dangerous level. You should
also avoid using a fuse that is too large or too small for the circuit, as this can compromise the
protection or cause nuisance tripping.
To install fuses safely and correctly, you need to follow some basic steps, such as turning off
the power supply, verifying the fuse ratings, using the appropriate tools and equipment, and
following the manufacturer's instructions. You should also check the condition of the fuse
holder, the connections, and the insulation.
To troubleshoot fuses, you need to identify the cause and location of the fault, and replace the
blown fuse with a new one of the same rating. You should use a multimeter or a continuity
tester to check the continuity of the fuse, and inspect it for any signs of melting, burning, or
cracking.
To maintain fuses and ensure their reliability and performance, you need to conduct regular
inspections, tests, and replacements. You should check the fuses for any physical damage,
corrosion, or deterioration, and measure their resistance and temperature.
To improve fuses and enhance their functionality and efficiency, you can use some advanced
features and technologies, such as;
Smart fuses which are fuses that can communicate with a control system or a network, and
provide information about their status, condition, and history.
Fuse indicators which are devices that can show whether a fuse has blown or not, and make it
easier to locate and replace the fuse.
Fuse links which are devices that can connect two or more fuses in parallel, and increase the
current rating or the redundancy of the circuit.
Fuse monitors which are devices that can measure and record the current, voltage, and power
of the fuse, and alert the user of any anomalies or faults.
Protection Of Installation By ELCB
An Earth Leakage Circuit Breaker (ELCB) protects electrical installations from electrical
shocks and fires by detecting and stopping current leakage:
ELCBs continuously monitor electrical systems for stray voltages on the metal enclosures of
electrical equipment. If a dangerous voltage is detected, the ELCB automatically trips and
disconnects the electricity supply.
ELCBs are usually located near the main electrical panel in homes and businesses.
ELCBs should be regularly tested and maintained to ensure they are working properly.
There are various types of ELCBs, each with different functions and usage. The standard rating
is 30mA, which is suitable for most residential and commercial applications.
Disadvantages
ELCBs can be susceptible to nuisance tripping, and may not protect against certain fault types
like overloads or short circuits. Initial installation and replacement costs can also be relatively
high.
More recent installations often use residual-current devices (RCDs, RCCBs, or GFCIs) instead
of ELCBs.
An ELCB is a specialised type of latching relay that has a building's incoming mains power
connected through its switching contacts so that the ELCB disconnects the power when earth
leakage is detected.
The ELCB detects fault currents from live to the Earth (ground) wire within the installation it
protects. If sufficient voltage appears across the ELCB's sense coil, it will switch off the power,
and remain off until manually reset. A voltage-sensing ELCB does not sense fault currents
from live to any other Earthed body.
Differences Between Solid Earthing Practice And Earth-Leakage Circuit Breaker
Protection
Solid earthing is a grounding method that connects a system supply directly to the ground,
while an Earth-leakage circuit breaker (ELCB) is an electrical safety device that protects people
and property from electrical faults:
Solid earthing
A system is solidly earthed when a system supply, such as a generator neutral or a transformer,
is connected directly to the ground. This method can help avoid excessive fault currents.
Earth-leakage circuit breaker
An ELCB is a safety device that protects against electrical faults and electric shock. ELCBs
can provide long-time protection against overload and short-time protection against shortcircuits. However, ELCBs may trip unnecessarily if used with older appliances that have a
small leakage. ELCBs may also be tripped by external voltages from something connected to
the earthing system.
Problems Associated With Earth-Leakage Circuit Breaker

They do not detect faults that do not pass current through the CPC to the Earth rod.

They do not allow a single building system to be easily split into multiple sections with
independent fault protection, because Earthing systems are usually bonded to pipework.

They may be tripped by external voltages from something connected to the Earthing
system such as metal pipes, a TN-S Earth or a TN-C-S combined neutral and Earth.

As with RCDs, electrically leaky appliances such as some water heaters, washing
machines and cookers may cause the ELCB to trip.

ELCBs introduce additional resistance and an additional point of failure into the
Earthing system.
Human Body Become Part Of Electric Circuit
The human body can become part of an electric circuit because it contains ions, which are
charged elements that conduct electricity:
Ions
The human body contains ions like sodium, potassium, and chloride, which are good
conductors of electricity.
Cell membranes
Cell membranes are insulators, but the fluids inside and outside of cells are electrolytes that
contain biochemical ions and are good conductors.
Action potentials
The movement of ions across cell membranes generates electrical pulses called action
potentials, which the nervous system uses to send signals throughout the body.
Energy production
The human body produces energy through muscle contractions, reactions in cells, and other
processes. At rest, the body generates about 100 watts of power, and during exercise, it can
generate up to 400 watts.
Electricity can interact with the body in several ways, including causing tissue injury and death.
The effects of electricity on the body can be difficult to understand because they are invisible
and intangible.
Our bodies conduct electricity. If any part of your body meets live electricity an electric current
flows through the tissues, which causes an electric shock. People sometimes call it
electrocution.
Electrical shock occurs when an electrical current travels through the body. Injuries from
electrical shock happen when someone accidentally comes in contact with an electrical source,
such as a frayed cord or a downed power line.
Causes
An electric shock occurs when someone has direct contact with a high-voltage current that
travels through the body.
Causes An Electric Shock
Several things can cause an electric shock, including:

Being struck by lightening

Contact with downed power lines

Putting fingers or objects into an electrical socket

Touching faulty or frayed electrical cords or appliances

Touching overloaded electrical outlets
Signs and Symptoms
Signs and symptoms of electrical shock can vary based on the type and amount of voltage.
Some may include:

Numbness and tingling

Burns

Seizures

Irregular heartbeat

Breathing irregularities or difficulty

Vision or hearing issues

Muscle spasms

Headaches

Loss of consciousness

Cardiac arrest
Symptoms caused by touching a frayed kitchen appliance cord are usually much less severe
than those caused by higher-voltage shocks from sources such as power lines or lightning.
Treatment
When electrical shock occurs outside, the treatment may also involve several steps to ensure
the area is safe before helping the victim, such as:

Examine the person visually but do not touch them. They can pass the electrical current
on to you if still connected to the electrical source.

Call help centre or have someone else call help centre.

Check for a source of electricity and turn it off if possible. If it's not possible, use an
object of non-conducting material, such as wood or plastic.

When you are sure you will be safe from electrical shock, check the victim's breathing
and pulse. Immediately begin cardiopulmonary resuscitation (CPR) if either has
stopped or appears unusually low.

If the victim is breathing but appears faint or has other signs of shock, lay them down
with their legs elevated. Bring the head slightly below the trunk of the body.

Do not treat any burns or remove clothing, and wait until help arrives.
At-Home Remedies
If a person or child experiences an electrical shock at home, contact your healthcare provider,
pediatrician, or call help centre. In some cases, shock can cause internal injuries that are
visually undetectable.
A healthcare provider can assess for surface burns, mouth burns, or other internal organ
injuries. If the person has severe burns, they may need to be admitted to the hospital for
treatment and observation.
Medical Care
Medical care for electrical shock will depend on the amount of voltage involved. Minor
incidence of electrical shock may not require medical care.
Treatment for less severe incidences of electrical shock may include pain medication, antibiotic
ointment, and dressing changes for minor burns.
Higher voltage injuries will require a higher level of care and often have poorer outcomes.
Emergency medical care may require:

Resuscitation

ICU care

IV fluids

Nutritional support

Surgery
When to See a Doctor
If you or a loved one experiences an electrical shock, it's important to be examined by a
healthcare provider.
The damage from an electrical shock depends on the voltage level, source, how it traveled
through the body, the person's age, and overall health.
Call help centre if a person with electrical shock has:

Irregular heartbeat

Muscle pain or muscle contractions

Confusion

Breathing problems

Cardiac arrest

Seizures

Loss of consciousness
Prevention
Best practices to prevent electrical shock in the home include:

Cover all outlets.

Ensure that wires are properly insulated and covered.

Keep wires away from children's reach.

Supervise children in areas with possible electrical hazards, such as electrical
appliances near a bathtub or pool.

Turn off the circuit breaker when working with electricity in the home.

Don't use electrical appliances in the bath or shower.
There are several ways to prevent electrical shock outside of the house, including:

Report any fallen or broken power lines immediately to your power company. Do not
touch them under any circumstances.

Do not drive or walk through standing water if power lines may have fallen in the water.

If you come in contact with a power line while in your car, stay in your car and drive
away if possible. If you are unable to drive away, stay in your vehicle and call
emergency services. Wait until emergency services arrive, and do not let anyone close
to your vehicle.

Call an electrician to fix electrical circuits that are wet or near water. If possible, turn
off power at the main breaker but never enter standing water to access it.

Never work on or near an electrical source while standing in water, especially if using
an electrical tool.

Make sure that electrical equipment is completely dry before restoring power.

Have a certified electrician confirm that turning the power back on is safe.

Turn off your main circuit breaker if there is a burning odour but no obvious source, or
if you can see sparks and frayed wires when you turn the power back on.

When installing or using a generator, talk to your utility company about usage. Don't
use generators without approved, automatic-interrupt devices. Generators can be a fire
hazard if they remain online once electricity resumes.
Artificial Respiration
Commencing artificial respiration is very simple and can very easily be successful. As time
passes, changes take place in the lungs that make it difficult for the casualty to respond well.
To carry out artificial respiration, you have to:
1. Keep the person lying on the floor, face up. This is the ideal posture.
2. Open the airway. There are different manoeuvres to open the airway, all of which are aimed
at placing the person in a position in which his tongue does not impede him from breathing.
The most correct method to keep the airway open is by placing one hand on the forehead and
the other on the lower jaw and inclining the person’s head backwards, thus producing
hyperextension of the neck. The airway may also be kept open by placing an object under the
shoulders, thus leaving the head dangling.
3. Check the person’s mouth and unclog it of any food remains, dentures, etc., if present.
4. Begin respiration: The most widely used method is mouth-to-mouth respiration.
To do this correctly, you must seal the person’s nose with one hand, fill your lungs with air,
place your mouth over the lips of the injured person and blow slowly (each insufflation should
last approximately 2 seconds). Separate your mouth from that of the injured person so that the
air can exit and insufflate again after 5 seconds. Remember that you should blow once every 5
seconds in adults.
When the air enters correctly, you will notice that you can empty your lungs without
encountering any resistance. The injured person’s chest will rise as air enters. If you blow very
quickly, the air will end up in the inured person’s stomach. Insufflation should be slow and
sustained.
Children under 7 years of age breathe more quickly than adults. Therefore, the first-aider
should blow once every 3 seconds, without totally emptying his lungs of air, as the thoracic
capacity of a child is less than that of an adult.
4.4. Other Artificial Respiration methods
Mouth-nose respiration: When there is injury to the mouth or it cannot be opened, artificial
respiration may be performed via the injured person’s nose.
To do so, keep the airway open, close the person’s mouth and blow through his nose once every
5 seconds.
Instrumental artificial respiration: An Ambu bag can be used; this is a device consisting of a
padded mask that fits over the patient’s face, covering the nose and mouth, which is connected
to a plastic pump. If you have one of these devices at your disposal, you should learn how to
use it.
Types of fire extinguisher & their uses
The different classes of fire extinguisher rating are listed below with the some of the most
suitable types of fire extinguisher for use on each class of fire:
Class A - Suitable for paper, wood & textiles.
Type of fire extinguisher - Water, Foam, Dry Powder, Wet Chemical
Class B - Suitable for flammable liquids.
Type of fire extinguisher - Foam, Dry Powder, Carbon Dioxide (CO2)
Class C - Suitable for flammable gasses.
Type of fire extinguisher - Dry Powder
Class F - Suitable for cooking oil and fat.
Type of fire extinguisher - Wet Chemical
Electrical Risk - Suitable for electrical equipment.
Type of fire extinguisher - Dry Powder, Carbon Dioxide (CO2)
Fire Extinguisher Colour Coding or Colour Bands
Current fire extinguishers in the UK are subject to strict standards and that includes their colour
coding or colour bands.
Fire extinguishers that meet the BS EN3 standard are manufactured with a red body and have
a zone band of a second colour, covering up to 10% of the surface, that indicate the
extinguisher’s contents. Each type of fire extinguisher has a particular zone of colour making
it easier for the user to identify the contents of the fire extinguisher.
Older fire extinguishers that pre-dated the current standard are still found. These extinguishers
were in colours other than the now predominantly red colour required to conform to BS EN3
and may still be legal. However, if they need to be replaced because they are unserviceable or
damaged, the new extinguisher needs to comply with the new requirements if it is to meet the
BS EN3 standard.
Typical colour zones of current fire extinguishers in the UK and the key features of each are:
Water Fire Extinguisher. Colour Zone - White
Dry Powder Fire Extinguisher. Colour Zone – Blue
Carbon Dioxide (CO2) Fire Extinguisher. Colour Zone – Black
Foam Fire Extinguisher. Colour Zone – Cream
Wet Chemical Fire Extinguisher. Colour Zone – Yellow
Content of Electricians Toolbox and Their Uses
An electrician's toolbox typically contains a variety of tools, including:
Pliers: Used for cutting, gripping, twisting, bending, or straightening wires. Electricians may
have a variety of pliers, including needle-nose, side-cutting, and reaming pliers.
Combination pliers
Combination pliers combine wire cutting and insulation stripping with serrated jaws, allowing
users to bend, twist and compress. Some models add additional functions or extended leverage.
Typically, the gripping jaws in combination pliers have a circular indentation to facilitate the
user’s hold on the target object. The flexibility of combination pliers ensures wide usage, both
by professional technicians and amateur.
Cutters
Cutters are a category of pliers designed primarily to cut materials. Diagonal cutters are used
for gripping and splicing wires in addition to cutting them, and they can also be used to strip
insulation for crimping and similar procedures. They're even useful for removing nails and
doing work via indentation. Diagonal cutters are also known as side or wire cutters and
‘nippers’, end cutters.
Flat nose pliers
Flat nose pliers are used for reshaping wire, either straightening or bending it, as well as
attaching ‘crimp beads’. Such beads are used to hold attachments in place – ‘crimping’ means
attachment via compression.
Flat nose pliers are widely used by jewellers.
Long nose pliers
Long nose pliers are a more delicate model used by electricians and engineers to grip, bend,
and shape and cut wires in confined spaces such as electrical boxes.
Long nose pliers are also known as needle nose pliers, long nose pliers, pinch nose pliers and
snipe nose pliers.
Multimeter: Measures multiple electrical properties, such as voltage, current, and resistance.
Continuity. Diodes, capacitor's value, frequency of an AC signal, Temperature measurement
etc. Voltmeter: Reads voltage levels to verify if circuits are on or off.
Fluke Digital Multimeters
Fluke digital multimeters are a widely used type of high-quality diagnostic multimeter
Fluke products tend to offer multiple functions and capabilities for testing numerous
components and circuits, with simultaneous voltage/resistance readouts displayed either
numerically or graphically via their large, easy-to-read LCD screens
Auto-Ranging Multimeters
Autoranging multimeters are among the most user-friendly of all designs; they automatically
adjust their measurement ranges to suit the type of readings you are trying to gauge or test. It
is also worth noting that most DMMs are auto-ranging nowadays.
Clamp Multimeters
Clamp multimeters combine the functions of a traditional DMM with that of a current sensor.
Integrated jaws allow users to attach the tool to a wire or other conductor anywhere in the
circuit without isolating or disconnecting a specific component first.
Wire strippers: Removes the plastic coating from wire without damaging it.
Gauged Wire Stripper
A gauged wire stripper is the basic type, these gauged wire strippers have precise notches for
easy operation. Once you choose the correct notch, stripping the cable could be accessible,
even if you have never stripped a cable.
Self-adjusting Wire Stripper
This is also named as an automatic wire stripper, it is an improved version of the typical wire
stripper. It helps strip the cable quickly without your effort as it automatically adjust to the
correct size and has a setting to control the length of your stripping.
Tape measure: it is a long, flexible ruler used to accurately measure the length of wiring,
distance.
Digital Tape Measure. Digital tapes are a type of construction measuring tape that uses digital
displays instead of traditional linear markings to show
Screwdrivers: Insulated screwdrivers are a common choice.
Flat Head Screwdriver
The correct term for a flathead screwdriver is a standard or slotted screwdriver. The term
"flathead" refers to the geometry of the screw head, and a flat-headed screw can have any type
of driving head.
Phillips
Also known as a cross-head screwdriver, this is a common type of screwdriver that fits
screws with a cross-shaped recess.
Electrical tape (or insulating tape); is a type of pressure-sensitive tape used to insulate
electrical wires and other materials that conduct electricity.
Cable ties: A cable tie organizes electrical cables and wires by binding them together. They are
made of metallic, non-metallic, and composite materials.
Other tools that may be found in an electrician's toolbox include:
Circuit finder
Fish tape
Knockout punch set
Conduit bender
Rechargeable screwdriver
Hole saw kit
Electricians may also use safety equipment such as insulated gloves, insulated matting, life
saving kits, rescue hooks, and operating rods.
To keep your tools organized, you can use a tool belt with pockets to segment your tools and
prevent them from shifting around. You can also group tools for your dominant hand together.
Uses Of Electrical/Electronics Workshop Tools
Electrical and electronic workshop tools are used for a wide range of tasks, including:
Repairing electronics
Tools like soldering stations, multimeters, oscilloscopes, signal generators, and bench power
supplies are used to diagnose and repair electronic devices.
Measuring
Tools like electricity meters, ESR meters, frequency counters, and leakage testers measure
electrical and electronic properties.
Safety
Tools like voltage testers are used to ensure that no current is flowing to a device or wire before
working on it.
Cutting, drilling, and bending
Tools like wire and cable cutters, wire strippers, and electric drills are used for cutting, drilling,
and bending.
Tightening and removing screws
Tools like screwdrivers are used for tightening and removing screws.
Gripping and handling components
Tools like pliers and tweezers are used for gripping, bending, and handling small components.
Other tools used in electrical and electronic workshops include: Crimpers, Tape measures,
Electrical tape, Cable ties, and Utility knives.
Procedure for Routine Inspection of Hand Tools
Examine each hand or power tool you and your crew will be using in detail. Check for
damages—like cracks, dents, or mushrooming—and ensure guards and other protective
equipment are properly installed when possible. Replace or send damaged tools for repairs
immediately.
Here are some things to check when performing a routine inspection of hand tools:
Physical damage: Check for cracks, fractures, punctures, or deformation of structural
components.
Blades and bits: Check for damage or cracking.
Handles: Check for damage, cracking, or looseness from the head of the tool.
Tips: Check for excessive wear on the tips of screwdrivers, chisels, or other similar tools.
Gripping surfaces: Check for wear on the gripping surfaces of pliers, wrenches, or other
similar tools.
Heads: Check that the heads of chisels are ground down and that the heads of chisels and
punches are not mushroomed.
Cutting tools: Check that cutting tools such as chisels and axes are sharp.
Storage: Use Snap-On or corks and Styrofoam when storing sharp hand tools.
Regular inspections are important for safety because constant use causes wear and tear. You
should also read and follow the manuals that come with your tools, as they have important
guidelines for keeping your equipment in good condition.
Differences between Hand Tools and Machine Tools
Hand tools are operated manually, and examples include hammers, screwdrivers, wrenches,
and more. Machine tools, on the other hand, are electrically - powered equipment such as drills,
saws, and sanders. Both hand tools and machine tools are used for a variety of purposes and
have their strengths and weaknesses.
It is a basic necessity to have hand and machine tools in any workshop to get any job done
efficiently and with greater precision.
Hand and machine tools are necessary any workshop for the following reasons;

They allow us to work more efficiently and productively.

They help us to avoid injuries by performing tasks that would otherwise be too difficult
or dangerous for us to do.

They help us create better quality products.
For example, Screwdriver allows for insertion and removal of screws easily. Hammer allows
nails to be driven into wood, while a saw helps cut through wood or metal
There are a variety of hand tools and machine tools available on the market, and each has its
own advantages and disadvantages.
Hand Tools
Hand tools are manually-operated tools that do not require any power source. They are often
smaller and lighter than power tools, which makes them easier to maneuver and use for
extended periods. Hand tools are also usually less expensive than power tools. On the
downside, hand tools can be slower and more labour-intensive than power tools.
Machine Tools
Machine tools are mechanical or electrical devices powered by a motor or battery. They are
typically faster and more powerful than hand tools, making them ideal for larger projects.
However, power tools can be more difficult to control than hand tools and can also be more
expensive.
To better understand the difference between these two tools, here’s a table breaking them down
according to precision speed, length of use, energy source, and safety:
Precision
Speed
Length of Use
Energy Source
Safety
Hand Tools
Machine Tools
Become more precise when
it comes to the level of
control
Slow
Depends on the frequency of
usage
Human power
Safe to use with proper
handling
Offer great precision for
repetitive tasks such as
drilling and cutting
Fast
Depends on the usage
Electricity, gas, or battery
Safe to use with proper
knowledge and safety
equipment
Here are some other differences between hand tools and machine tools:
Versatility: Hand tools are more versatile and can be used for a wider range of tasks.
Cost: Hand tools are more affordable than machine tools.
Maintenance: Hand tools are easier to maintain than machine tools.
Power: Machine tools are more powerful than hand tools.
Examples: Examples of hand tools include hammers, screwdrivers, and wrenches. Examples
of machine tools include lathes and drilling machines.
Types of Insulating and Conducting Materials
Conductors?
Conductors are the materials or substances which allow electricity to flow through them. They
conduct electricity because they allow electrons to flow easily inside them from atom to atom.
Also, conductors allow the transmission of heat or light from one source to another.
Metals, humans, earth, and animals are all conductors. This is the reason we get electric shocks!
Moreover, the human body is a good conductor. So it provides a resistance-free path for the
current to flow from wire to body.
Conductors have free electrons on its surface which allow current to pass through easily. This
is the reason why conductors are able to conduct electricity.
Here are some types of insulating and conducting materials:
Conductors
Materials that allow electricity to flow through them, such as metals, graphite, Mercury, silver
and aqueous solutions of salts. Copper and aluminum are common metals used in electricity.
Conductors are quite useful in many ways. They find use in many real-life applications. For
example,
Mercury is a common material in thermometer to check the temperature of the body.
Aluminium finds its use in making foils to store food. It is also used in the production of fry
pans to store heat quickly.
Iron is a common material used in vehicle engine manufacturing to conduct heat.
The plate of iron is made up of steel to absorb heat briskly.
Conductors find their use in car radiators to eradicate heat away from the engine.
Insulators
Insulators are the materials or substances which resist or don’t allow the current to flow through
them. In general, they are solid in nature. Also, insulators are finding use in a variety of systems.
As they do not allow the flow of heat. The property which makes insulators different from
conductors is its resistivity.
Wood, cloth, glass, mica, and quartz are some good examples of insulators. Also, insulators
are protectors. They give protection against heat, sound and of course passage of electricity.
Furthermore, insulators don’t have any free electrons. It is the main reason why they don’t
conduct electricity.
Thermal insulators
Materials that trap air within themselves to insulate against heat, such as fiberglass, cellulose,
rock wool, and styrofoam.
Acoustic insulators
Materials that can offer good acoustic insulation, such as many of the same materials used for
thermal insulation.
Inorganic materials
Materials used in high voltage overhead lines as suspension insulators or as bushings on high
voltage transformers and switchgears.
As insulators resist the flow of electron, they find worldwide applications. Some of the
common uses include:
Thermal insulators, disallow heat to move from one place to another. Hence, we use them in
making thermoplastic bottles. They are also used in fireproofing ceilings and walls.
Sound insulators help in controlling noise level, as they are good in absorbance of sound.
Thus, we use them in buildings and conference halls to make them noise-free.
Electrical insulators hinder the flow of electron or passage of current through them. So, we
use them extensively in circuit boards and high-voltage systems. They are also used in coating
electric wire and cables.
Difference between Conductors and Insulators
Conductors
Insulators
Conductors are used in making electrical
equipment.
A conductor allows current to flow easily
through it.
Electric charge exists on the surface of
conductors
Conductors don’t store energy when kept in a
magnetic field
Thermal conductivity ( heat allowance) of a
conductor is very high
The resistance of a conductor is very low
Copper, Aluminium, and Mercury are some
conductors
Insulators are used in insulating electrical
equipment for safety purpose
Insulators don’t allow current to flow through it.
Electric charges are absent in insulator.
Insulators store energy when kept in a magnetic
field
Thermal conductivity of an insulator is very low
The resistance of insulator is very high
Wood, paper and ceramic are some insulators
Electrical Cable?
The cable that is used for the transmission and distribution of electrical power is known as the
electrical power cable.
The power cable is made of three main components, namely, conductor, dielectric, and sheath.
The conducting path for the current in the cable is provided by the conductor. The insulation
or dielectric withstands the service voltage and isolates the live conductor with other objects.
The sheath does not allow the moistures to enter and protects the cables from all external
influences like chemical or electrochemical attacks and fire.
Cables are classified into 5 types depending upon their purpose as follows:
Ribbon Electric Cables
It consists of multiple insulated wires running parallel with one another and is used for
transmission of multiple data simultaneously. For example, this is used to connect the CPU
with the motherboard and is generally used for the interconnection of networking devices.
Shielded Cables
It consists of 1 or 2 insulated wires which are covered by a woven braided shield or aluminium
Mylar foil for better signal transmission and removing irregularities in the frequency of power
and external interference in radio. These cables transmit high voltage electric current and are
protected by a shield.
Twisted Pair Cables
It has two or more insulated copper wires which are twisted with each other and are colourcoded. These types of wires are usually used in telephone cables and the resistance to external
interference can be measured by the number of wires.
Coaxial Cables
This consists of solid copper or steel conductor plated with copper which is enclosed in the
metallic braid and metallic tape. This is entirely covered with an insulated protective outer
jacket. These types of cables are used for computer networking and audio-video networking.
Fibre Optics Cable
There are these types of cables which transport optical data signals from an attached light
source to the receiving device.
Cable Construction
Within my Cable Engineering, we consider standard cable constructions. Cables which vary
from this may be simulated using approximations to the standard construction or particular case
additions.
Low Voltage Cable Construction
Cables follow the typical construction pattern of the conductor, insulation, bedding, armour
and outer sheath. Conductors are either copper or aluminium.
CONDUCTOR SHAPE
Cable conductors can take various shapes. IEC 60228 "Conductors of insulated cables",
identifies three main conductor shapes:
1. Circular
2. Circular compacted
3. Shaped
The shaping of conductors takes place during the manufacturing process and can result in
improvements in conductor dimensions and a.c. resistance.
Stranded
Stranded conductors consist of individual wires bound together to form the larger
conductor. Standed improves the flexibility of conductors and reduces the overall inductance.
IEC 60228 "Conductors of insulated cables", gives guidelines on the minimum number of wires
in a stranded conductor for various cross-sectional areas.
High Voltage Cable Construction
The construction of high voltage cables is similar to that of low voltage. Typically conductor and insulation
screens are added to prevent air-filled cavities which would lead to electric discharges.
Where armour is not needed, it may still be desirable to have a metallic outer screen for
functional reasons. This could consist of tapes or a braid, or concentric layer of wire or a
combination of wires and tapes.
Cable Build up
Conductors - normally copper, aluminium or aluminium allow class 1 or class 2 in
accordance with IEC 60228.
Insulation - extruded dielectric (various types in use).
Screening - medium and high voltage cables have a metallic layer surround the cores (either
individually or collectively).
- conductor: non-metallic, semi-conducting layer
- insulation: non-metallic, semi-conducting layer and metallic screen
- collective: semi-conducting inner covering, and metallic screen (overall laid up cores)
Metallic Layers - metallic screen: wires or tapes
- concentric conductor: electrical resistance dictated by regulation
- metallic sheath: typically lead or lead alloy tube
- metallic armour: flat wire, round wire or double tape (sometimes braided)
Separation sheath (bedding) - applied where the underlying metallic layer and armour are of
different materials. Applied between laid up cores and armour of low voltage cables.
Oversheath - the outer covering of the cable.
Advantages and Disadvantages of P.V.C Shealthed over P.V.C Insulated
Cables
PVC Cables. Polyvinyl Chloride is what PVC in a PVC cable stands for. Generally, any electric
wire that has a Polyvinyl Chloride jacket or insulation is referred to as a PVC cable. They are
widely used because of their high chemical, water, and heat resistance while being extremely
flexible and sturdy
PVC sheathed and insulated cables have many advantages, but they also have some potential
disadvantages:
Advantages
Durability: PVC is resistant to abrasion, chemicals, oil, moisture, and weather conditions.
Flexibility: PVC is flexible, making it easier to install in tight spaces and complex routes.
Flame retardant: PVC can be made flame retardant, which is important for electrical cables.
Cost-effective: PVC is generally economical.
Recyclable: PVC is easy to process and recycle.
Long service life: PVC cables can often exceed a 25-30 year service life.
Disadvantages
Chemical reaction with expanded polystyrene: PVC sheathed cables can react with
expanded polystyrene, causing the cable to crack and split.
Fire hazard: When burned, PVC can produce black smoke, hydrochloric acid, and other
harmful gases.
Environmental conditions: Prolonged UV exposure can age and deteriorate the cable's
insulation layer and sheath.
Physical stress: PVC can break and splinter when exposed to physical stress.
Sagging: PVC needs to be supported when installed in longer runs due to sagging.
Advantages and Disadvantages of Metal Sheathed over Mineral Insulated
Cables
Metal sheathed cables and mineral insulated cables have different advantages and
disadvantages, including:
Metal sheathed cables
These cables are durable and robust, and can protect against physical damage, corrosion,
moisture, and chemical exposure. However, lead sheathed cables can be heavy, which can
make them more expensive to install.
Mineral insulated cables
These cables are low flammability, even at high temperatures, and are resistant to oxidation.
They also have a wide temperature range, are easy to handle, and have a long product life time.
However, they can be more expensive than PVC cables, and installation and termination
require special training and kits. They are also not suitable for use where they will be subject
to vibration or flexing.
Here are some more advantages and disadvantages of mineral insulated cables:
Advantages
Non-reactive insulation
Insulation doesn't burn
High levels of precise accuracy
Disadvantages
Terminations are vulnerable to fire, moisture, and mechanical impact
Not suitable for use where it will be subject to vibration or flexing
General IEEE Wiring Regulations Related to Cables and Their Uses
Here are some IEE wiring regulations related to cables and their uses:
Cable colours
The International Electrical Commission Standard IEC 60446 governs the colours of electrical
cables. The colours for identifying conductors include:
Neutral conductor: Blue
Phase conductor: Black, grey, or brown
Protective or earthing conductor: Two colours, yellow and green
Cable classification
Power cables are classified as low voltage, medium voltage, or high voltage. They can also be
classified by insulation, such as plastic, rubber, or mineral.
Electrical installation safety
The IEE Wiring Regulations have several requirements for cables and their use, including:
Mechanical protection
Cables used outdoors must have adequate mechanical protection and support to avoid strain.
Spacing and bends
Tables in the IEE Regulations show the required spacing for supports and the minimum radius
for bends.
RCD protection
Cables concealed in walls or partitions must have additional RCD protection, unless they have
other protection, such as mechanical protection.
Insulation resistance
The minimum insulation resistance for SELV and PELV circuits is 0.5 M ohm when tested at
250 V, and 1 M ohm for systems up to 500 V.
Ring circuits
The cable rating must be at least two thirds of the rating of the protective device.
IEE regulations require electrical installations to be constructed and maintained to ensure the
safety of people. This includes:

Sizing and rating parts appropriately

Insulating parts appropriately

Earthing exposed metallic parts

Fitting protective devices

Isolating the electricity supply

Labeling parts

Inspecting and testing installations
The IEE regulations are the latest edition of the Wiring Regulations published by the Institution
of Electrical Engineers (BS 7671)
The cable colour coding, commonly used in Nigeria
The common colour coding for electrical wires in Nigeria is:
Red: Live wire
Black: Neutral wire
Yellow/green: Earth wire
Here are some other electrical wire colour codes:
White or gray: Neutral wire
Green or bare: Grounding wire
Brown: Live wire
Blue: Neutral wire
Different Wiring Methods
What is Electrical Wiring?
Electrical Wiring is a process of connecting cables and wires to the related devices such as
fuse, switches, sockets, lights, fans etc. to the main distribution board is a specific structure to
the utility pole for continues power supply.
Methods of Electrical Wiring Systems w.r.t Taking Connection
Wiring (a process of connecting various accessories for distribution of electrical energy from
supplier’s meter board to home appliances such as lamps, fans and other domestic appliances
is known as Electrical Wiring) can be done using several methods.
Here are some different wiring methods:
Conduit wiring
Conduits are installed on the surface of a wall or roof. The size of the conduit depends on the
number of wires that will pass through it. It is divided into Surface Conduit Wiring and
Concealed Conduit Wiring.
Surface Conduit Wiring
If conduits installed on roof or wall, IT is known as surface conduit wiring. In this wiring
method, PVC or galvanised pipes are mounted on the surface of wall with the help of clips and
or rawal plugs.
Concealed Conduit wiring
If the pipes and cables are hidden inside the wall with the help of plastering, it is called
concealed conduit wiring. In other words, the electrical wiring system inside wall, roof or floor
with the help of plastic or metallic piping is called concealed conduit wiring. Obliviously, It is
the most popular, beautiful, stronger and common electrical wiring system nowadays.
Note: the pipes used in conduit wiring could be metallic or non-metallic material. Any of the
material can be used either surface or concealed conduit.
Advantage of Conduit Wiring Systems

It is the safest wiring system (Concealed conduit wring)

Appearance is very beautiful (in case of concealed conduit wiring)

No risk of mechanical wear & tear and fire in case of metallic pipes.

Customization can be easily done according to the future needs.

Repairing and maintenance is easy.

There is no risk of damage the cables insulation.

It is reliable and popular wiring system.

Sustainable and long-lasting wiring system.
Disadvantages of Conduit Wiring Systems

It is expensive wiring system (Due to PVC and Metallic pipes, Additional earthing for
metallic pipes Tee(s) and elbows etc.

Very hard to find the defects in the wiring.

Installation is not easy and simple.

Risk of electric shock (In case of metallic pipes without proper earthing & grounding
system)

Very complicated to manage additional connection in the future.
Casing and capping wiring
This method was once common, but is now considered obsolete. It uses insulated cables like
VIR or PVC. The cables were carried through the wooden casing enclosures. The casing is
made up of a strip of wood with parallel grooves cut length wise so as to accommodate VIR
cables. The grooves were made to separate opposite polarity. The capping (also made of wood)
used to cover the wires and cables installed and fitted in the casing.
Advantages of Casing Capping Wiring:

It is cheap wiring system as compared to sheathed and conduit wiring systems.

It is strong and long-lasting wiring system.

Customization can be easily done in this wiring system.

If Phase and Neutral wire is installed in separate slots, then repairing is easy.

Stay for long time in the field due to strong insulation of capping and casing.

It stays safe from oil, Steam, smoke and rain.

No risk of electric shock due to covered wires and cables in casing & capping.
Disadvantages Casing Capping Wiring:

There is a high risk of fire in casing & capping wiring system.

Not suitable in the acidic, alkalies and humidity conditions

Costly repairing and need more material.

Material can’t be found easily in the contemporary

White ants may damage the casing & capping of wood.
Cleat wiring
This method is easy to install and customize, and wires are easy to see and repair. However, it
may not look very good. Cleat wiring system is a temporary wiring system that comprises of
ordinary VIR or PVC insulated wires (occasionally, sheathed and weather proof cable) braided
and compounded held on walls or ceilings by means of porcelain cleats, Plastic or wood.
Advantages of Cleat Wiring:

It is simple and cheap wiring system

Most suitable for temporary use i.e. under construction building or army camping

As the cables and wires of cleat wiring system is in open air, Therefore fault in cables
can be seen and repair easily.

Cleat wiring system installation is easy and simple.

Customization can be easily done in this wiring system e.g. alteration and addition.

Inspection is easy and simple.
Disadvantages of Cleat Wiring:

Appearance is not so good.

Cleat wiring can’t be use for permanent use because, Sag may be occur after sometime
of the usage.

In this wiring system, the cables and wiring is in open air, therefore, oil, Steam,
humidity, smoke, rain, chemical and acidic effect may damage the cables and wires.

It is not lasting wire system because of the weather effect, risk of fire and wear & tear.

It can be only used on 250/440 Volts on low temperature.

There is always a risk of fire and electric shock.

It can’t be used in important and sensitive location and places.

It is not lasting, reliable and sustainable wiring system.
Lead sheathed wiring
This method uses electrical conductors encased in an aluminum alloy that is 95% lead. The
coating protects the cables from corrosion and damage caused by moisture and mechanical
stress.
Trunking
There are various types of trunking systems, including cable trunking, bus-bar trunking,
lighting trunking, and multi-compartment trunking. This is similar to surface conduit wiring
system.
Batten Wiring (CTS or TRS)
Single core or double core or three core TRS cables with a circular oval shape cables are used
in this kind of wiring. Mostly, single-core cables are preferred. TRS cables are chemical proof,
water proof, steam proof, but are slightly affected by lubricating oil. The TRS cables are run
on well-seasoned and straight teak wood batten with at least a thickness of 10mm. The cables
are held on the wooden batten by means of tinned brass link clips (buckle clip) already fixed
on the batten with brass pins and spaced at an interval of 10cm for horizontal runs and 15cm
for vertical runs.
Advantages of Batten Wiring

Wiring installation is simple, cheap and easy

Repairing is easy

strong and long-lasting

Customization can be easily done in this wiring system.

Less chance of leakage current in batten wiring system
Disadvantages of Batten Wiring

Can’t be install in the humidity, Chemical effects, open and outdoor areas.

High risk of firs

Not safe from external wear & tear and weather effects (because, the wires are openly
visible to heat, dust, steam and smoke.

Heavy wires can’t be used in batten wiring system.

Only suitable below then 250V.

Need more cables and wires.
Factors Associated with the Choice of a Particular Wiring System.
When choosing an electrical wiring system, the following factors should considered:
Cost: The initial cost of the wiring system is a key factor.
Safety: The wiring system should be safe against hazards like fire, electrical shocks, and
moisture.
Type of load: The type of load, such as light, HVAC, or motors, will affect the wiring system.
Future modifications: Consider the possibility of future modifications or extensions.
Environmental conditions: The environmental conditions, such as temperature, moisture, and
exposure to sunlight and chemicals, will affect the wiring system.
Cable type: The type of wire or cable used, including the conductor material, insulation, and
protective coverings, will affect the wiring system.
Wire gauge: The thickness of the wire, or wire gauge, will affect the wiring system.
Voltage rating: The voltage rating of the wire will affect the wiring system.
Current carrying capacity: The current carrying capacity of the wire will affect the wiring
system.
Short circuit rating: The short circuit rating of the wire will affect the wiring system.
Voltage regulation: The voltage regulation of the wire will affect the wiring system.
Wiring safety codes vary by locality, country, or region.
The Uses of Pattresses and Blocks for Electrical Wiring.
A pattress box is a surface mounted wall box that is used to house the wiring and connections
for an electrical accessory, such as a light switch or plug socket. It is a plastic surface mounted
wall box, but can also be covered in a metal finish to match with electrical accessories.
Pattress boxes are used for connecting electrical accessories to the cabling in a house. They are
typically used when it is not possible or preferable to use a back box fitted within a wall, such
as a metal or plastic back box.
A back box is mounted within a wall, so that the front of the back box is flush or set back from
the level of the plaster. A pattress box is fitted to the surface of the wall, so all the sides of the
pattress box are exposed.
How to Fix the Cables to a Back Box
It is advisable to feed the cables through the back of the plastic pattress box, leaving the fours
sides untouched.
If this is not possible, it is possible to carefully drill a hole in the metal and plastic back box,
and fit a rubber grommet. In this case it is possible to fit the cabling into conduit that can butt
up against the back box.
Size Pattress Box
Pattress boxes are available in two standard widths. These correspond to the width of a single
or double electrical plate, and need to be chosen accordingly.
The Steps for Preparing Requisition for Wiring Materials.
1. Assess the project scope and requirements
Before you start any electrical installation project, you need to assess the scope and
requirements of the project. This means you need to understand the purpose, goals,
specifications, and expectations of the project. You also need to identify the resources,
materials, tools, equipment, and personnel needed for the project. You should also check the
site conditions, safety hazards, codes, regulations, and permits that apply to the project. By
assessing the project scope and requirements, you can avoid surprises, misunderstandings, and
conflicts later on.
2. Create a detailed project plan and schedule
Once you have assessed the project scope and requirements, you need to create a detailed
project plan and schedule. This means you need to break down the project into manageable
tasks, assign responsibilities, set deadlines, and allocate resources. You should also
communicate the project plan and schedule to all the stakeholders, including the client, the
team, the suppliers, and the subcontractors. By creating a detailed project plan and schedule,
you can monitor the progress, track the performance, and manage the changes of the project.
3. Prepare the site and the materials
Before you start the installation work, you need to prepare the site and the materials. This
means you need to inspect the site, clear any obstructions, mark any hazards, and secure any
access points. You also need to check the materials, verify the quantities, quality, and
compatibility, and store them properly. You should also test the tools, equipment, and safety
devices, and make sure they are in good working condition. By preparing the site and the
materials, you can prevent accidents, damages, and delays during the installation work.
4. Follow the installation instructions and standards
During the installation work, you need to follow the installation instructions and standards.
This means you need to follow the manufacturer's guidelines, the client's specifications, and
the industry's best practices when installing the electrical components and systems. You should
also follow the safety rules, the code requirements, and the quality standards when performing
the installation work. By following the installation instructions and standards, you can ensure
the accuracy, functionality, and reliability of the electrical installation.
5. Check and test the installation work
After the installation work, you need to check and test the installation work. This means you
need to inspect the installation work, look for any errors, defects, or deviations, and correct
them if needed. You also need to test the installation work, measure the performance,
functionality, and efficiency of the electrical components and systems, and verify that they
meet the expectations and requirements. By checking and testing the installation work, you can
ensure the satisfaction, compliance, and safety of the electrical installation.
6. Document and report the installation work
After the installation work, you also need to document and report the installation work. This
means you need to record the installation work, document any changes, issues, or incidents that
occurred during the project, and collect any feedback or suggestions from the stakeholders.
You also need to report the installation work, communicate the results, outcomes, and
achievements of the project, and provide any recommendations or follow-ups for future
improvements. By documenting and reporting the installation work, you can demonstrate the
value, quality, and professionalism of your electrical installation service.
Modular wiring systems and accessories
Modular wiring refers to an electrical system that uses standardised components that can be
easily connected and disconnected.
This allows for flexibility and ease of maintenance, making it a popular choice in residential,
commercial, and industrial settings.
Modular wiring systems are typically pre-wired and tested, reducing installation time and
labour. They are also easy to troubleshoot and repair due to the accessibility of individual
components. In addition, modular wiring systems can be easily modified or expanded as
needed.
Basic Requirements for Testing and Inspection of Electrical Installation
The basic requirements for testing and inspecting an electrical installation include:
Visual inspection: Check for breaks, cracks, overheating, and other signs of damage.
Documentation: Gather all relevant documentation, including electrical diagrams, wiring
plans, equipment manuals, and maintenance records.
Insulation resistance: Check for faults between the installation and earth, and between
conductors.
Earth fault loop impedance: Confirm that the earthing system is effective and can activate
the protective device in case of a fault.
Circuit connections: Ensure that circuits are connected correctly to avoid safety hazards.
Automatic disconnection of supply: Test the automatic disconnection of supply.
Polarity, functional, and operational tests: Perform polarity, functional, and operational
tests.
Voltage drop: Measure the voltage drop.
The purpose of testing an electrical installation is to determine if it's safe to use, or if it needs
to be repaired or replaced.
Electrical Diagrams of Testing Procedures
Instruments for Testing and Inspection Work.
In order to carry out the verification process proficiently, the person conducting the inspection
and test must be in possession of suitable test instruments.
The commonly used instruments for electric wiring testing and inspection include:
 Polarity Tester
 Continuity tester (low ohms).
 Insulation resistance tester.
 Loop impedance tester.
 Residual current device (RCD) tester.
 Prospective fault current (PFC) tester.
 Approved test lamp or voltage indicator.
 Proving unit.
Nowadays we have dual or multifunction instruments, so you may have continuity and
insulation resistance in one unit, loop impedance and PFC tests in one unit and loop impedance,
PFC and RCD tests in one unit, and so on.
Polarity Tester
A polarity test is a crucial safety check that verifies the correct connection of live and earth
conductors in an electrical installation. It's important to ensure that the phase and neutral
conductors are not reversed, and that the neutral is continuous and earthed.
The polarity test is important for the following reasons:
Safety: Incorrect polarity can lead to serious consequences, such as electrocution, fire, or
damage to electrical appliances.
Accuracy: It's important to perform polarity testing thoroughly and accurately.
Compliance: Polarity testing is required by regulation.
Continuity Tester (Low Resistance Ohmmeter)
A continuity test verifies that current will flow in an electrical circuit (i.e. that the circuit is
continuous). The test is performed by placing a small voltage between 2 or more endpoints of
the circuit. In continuity testing the resistance between two points is measured. Low resistance
means that the circuit is closed and there is electrical continuity.
A continuity tester should have a no-load source voltage between 4 to 24 V and capable of
delivering an AC or DC short circuit (not less than 200 mA). It should have a resolution, that
is, detectable difference in resistance of at least 0.05 m𝝮.
Insulation Resistance Tester
Insulation testers use a high voltage, low current DC charge to measure the resistance within
wires and motor windings to identify current leakage and faulty or damaged insulation, which
can lead to arc faults, blown circuits, and risk of electrical shock or fire. Megohmmeters are
ideal for monitoring machine health and improving preventative maintenance efforts.
An insulation resistance tester must be capable of delivering 1 mA when the required test
voltage is applied across the minimum acceptable value of insulation resistance. Accordingly,
an instrument selected for use on a low-voltage system should be capable of delivering 1 mA
at 500 V across a resistance of 1 m𝝮.
Ring Circuit Loop Impedance Testing
The phase conductor of one side of the ring and the neutral from the other (P1 and N2) are
connected together, and a low resistance ohmmeter used to measure the resistance between
the remaining phase and the neutral (P2 and Ni).
Loop impedance testing ensures proper operation of protective devices:
Use a multifunction test instrument to measure loop impedance (Zs).
Test from each socket outlet, ensuring values are within acceptable limits.
Test to confirm the continuity of a ring final circuit
Test of Effectiveness of Earthing Tester
Testing of earthing systems enables confirmation of the design values and safe operation in
the case of a fault condition according to the applicable safety standards and criteria.
Current injection testing is a methodology which facilitates comprehensive testing of buried
earthing systems.
Checking Earthing with a Multimeter/Test Lamp
Set a multimeter to measure AC voltage, Plug the red and black leads into the matching ports
on the multimeter. Take a reading while the leads are in the live and neutral ports of an outlet.
Check the voltage when the leads are inserted to the live and earthing ports.