Terminating and connecting electrical wiring and electronic circuits

WEB SCRIPT Electrical and Electronics
Sector:
Qualification: Electronics Products Assembly and Servicing NC II
Unit of Competency:
Module Title: Terminate and Connect Electrical Wiring and Electronic Circuits

Learning Outcomes: Terminating and Connecting Electrical Wiring and Electronic Circuits
LO1: Plan and prepare for termination/ connection of Electrical
Developer/s: wiring/electronics circuits
Anna Marie Gime

TITLE Planning and preparing for termination/ connection of Electrical
OBJECTIVES
wiring/electronics circuits
INTRODUCTION
Topic 1 In this lesson, you will learn to plan and prepare for
termination/connection of electrical wiring/ electronics circuits that you
can apply in the real - life situation
The Termination/ connection of electrical wiring and electronics
connections applies to the connection of wiring and includes termination
and connection of all types of cords and cables, excluding specialist
cables. If you're planning any electrical project, learning the basics of
wiring materials and installation is the best place to start.

Ways to Check and Prepare the materials

Lesson 1 Ways to Check and Prepare the materials

Checking and Preparing the materials, tools and equipment needed are important so you become
familiar with this thing and the proper use of this instrument according to the needs.

1.1 Ways to Check and Prepare the materials

Materials was one of the basic needs in terms of electrical wiring and electronics circuit, let's start
first for the simple electronics circuit materials.

Components of simple Circuit and Electrical Wiring

1. ·AC/DC source
DC (Direct Current) - when the power is running an electrical circuit moves charge with
only one direction . Current flow with positive(+) and negative (-). In DC Circuit, the power
source supplies the electrons, batteries dricicand photoelectric cells are example DC
current.
AC (Alternative Current) - When the power source driving electrical circuit moves charge
back and forth (just continually changes direction when it flows).
In AC current, you supply the electrons

Components of AC/DC source
 Power Supply - provides electric potential difference between its terminal.

 The device transforms energy from one form of energy ( such as chemical ) into
electrical energy.

 Connecting Wires - provide a path for electrical current to flow.
 Consumers(or loads)- Any electrical device connected to the circuit.

Materials that are possibly to use:
 Equipment that will operate on either an AC or DC power source

 Battery – a dc voltage source containing two or more cells that convert chemical
energy to electrical energy.

 Cell – Single unit used to convert chemical energy into a DC electrical voltage.
Source: https://kapitolyohs.files.wordpress.com/2011/06/terminating-and-connecting-of-electrical-
wirings-and-electronics-circuits-2nd.pdf

2. . FUSE
Once you design a simple circuit on electronics, it is important to include a fuse in the primary or
secondary of a transformer.
Fuse is a safety device used to protect an electrical circuit from the effect of excessive current. Its
essential component is usually a strip of metal that will melt at a given temperature. A fuse is so
designed that the strip of metal can easily be placed in the electric circuit. If the current in the
circuit exceeds a predetermined value, the fusible metal will melt and thus break, or open the
circuit.
A fuse is usually rated in Amperes, which represents the maximum continuous current it could
handle without blowing.
The most popular type of fuse in Electronics is 3AG type. This code describes the case size and
material with the “G” indicating a glass material and “A” indicating that it is intended for automotive
application. A 3AG fuse measures approximately 32mm x 6mm.
Source: https://kapitolyohs.files.wordpress.com/2011/06/terminating-and-connecting-of-electrical-
wirings-and-electronics-circuits-2nd.pdf

Types of fuse (this will be use in electronics circuit)
 Rewirable Fuses. This type of circuit is mostly used in the small current circuit or for
domestic wiring. ...
 Totally Enclosed or Cartridge Type Fuses. ...
 Dropout Fuse. ...
 Striker Fuse. ...
 Switch Fuse. ...
 Cartridge Type HV HRC Fuse. ...
 Liquid Type HV HRC Fuse. ...
 Expulsion Type HV Fuse.

Source: Designed by Derrick L. Lo.

3. Wires and Cable

A wire is a single slender rod or filament of drawn metal. This definition restricts the term to what
would ordinarily be understood as solid wire. The word “slender” is used because the length of a
wire is usually large when compared to its diameter. If a wire is covered with insulation, It is an
insulated wire. Although the term “wire” properly refers to the metal, it also includes the insulation.

A conductor is a wire suitable for carrying an electric current.

A stranded conductor is a conductor composed of a group of wire or of any combination of groups
of wires. The wires in a stranded conductor are usually twisted together and not insulated from
each other.

A cable is either a stranded conductor (single-conductor cable) or a combination of conductors
insulated from one another (multiple-conductor cable). The term “cable” is a general one and
usually applies only to the large sizes of conductor. A small cable is more often called a stranded
wire or cord (such as that used for an iron or a lamp cord). Cables may be bare or insulated.
Insulated cables may be sheathed (covered) with lead, or protective armor.

Source: https://kapitolyohs.files.wordpress.com/2011/06/terminating-and-connecting-of-electrical-
wirings-and-electronics-circuits-2nd.pdf

Types of wires

 Triplex Wires: Triplex wires are usually used in single-phase service drop
conductors, between the power pole and weather heads. They are composed of
two insulated aluminum wires wrapped with a third bare wire which is used as a
common neutral. The neutral is usually of a smaller gauge and grounded at both
the electric meter and the transformer.

 Main Feeder Wires: Main power feeder wires are the wires that connect the
service weather head to the house. They’re made with stranded or solid THHN wire
and the cable installed is 25% more than the load required.

 Panel Feed Wires: Panel feed cables are generally black insulated THHN wire.
These are used to power the main junction box and the circuit breaker panels. Just
like main power feeder wires, the cables should be rated for 25% more than the
actual load

 Non-Metallic Sheathed Wires: Non-metallic sheath wire, or Romex, is used in

most homes and has 2-3 conductors, each with plastic insulation, and a bare
ground wire. The individual wires are covered with another layer of non-metallic
sheathing. Since it’s relatively cheaper and available in ratings for 15, 20 and 20
amps, this type is preferred for in-house wiring.

 Single Strand Wires: Single strand wire also uses THHN wire, though there are
other variants. Each wire is separate and multiple wires can be drawn together
through a pipe easily. Single strand wires are the most popular choice for layouts
that use pipes to contain wires.

Source: https://www.quora.com/What-are-the-different-types-of-wires

Types of cables

Electrical cable types

 Coaxial cable – used for radio frequency signals, for example in cable television distribution
systems.

 Communications cable
 Direct-buried cable
 Flexible cables
 Heliax cable
 Non-metallic sheathed cable (or nonmetallic building wire, NM, NM-B)
 Metallic sheathed cable (or armored cable, AC, or BX)
 Multicore cable (consist of more than one wire and is covered by cable jacket)
 Paired cable – Composed of two individually insulated conductors that are usually used in

DC or low-frequency AC applications
 Portable cord – Flexible cable for AC power in portable applications
 Ribbon cable – Useful when many wires are required. This type of cable can easily flex, and

It is designed to handle low-level voltages.
 Shielded cable – Used for sensitive electronic circuits or to provide protection in high-

voltage applications.
 Single cable (from time to time this name is used for wire)
 Submersible cable
 Twinax cable
 Twin-lead – This type of cable is a flat two-wire line. It is commonly called a 300 Ω line

because the line has an impedance of 300 Ω. It is often used as a transmission line
between an antenna and a receiver (e.g., TV and radio). These cables are stranded to lower
skin effects.
 Twisted pair – Consists of two interwound insulated wires. It resembles a paired cable,
except that the paired wires are twisted

Source: https://www.systemswire.com/electrical-cable-types/

Source: Copyright Circuit digest

4. Switch and its function

Switch is a device used to break an electric current or transfer it to another conductor. Switches
are commonly used to open or close a circuit. Closed is the ON position, while open is the OFF
position. Normally, a switch is installed in series with the line carrying current from the power
source to the load.

A switch is a mechanical device used to connect and disconnect a circuit at will. Switches cover a
wide range of types, from sub-miniature up to industrial plant switching megawatts of power on
high voltage distribution lines.

Switch is a manually operated device capable of making, breaking, or changing the connection in
an electronics or electrical circuit. A switch connected in series with one of the connecting wires of
a simple circuit affords a means of controlling the current in the circuit.

Source: en.wikipedia.org

Switched function

 When the switch is closed, the electron finds an interrupted path in the circuit.

 Open is the OFF position of the switch, while closed is the ON position.

 When the switch is opened, the current delivered by the power supply is normally
insufficient to jump the switch gap in the form of an arc and the electron flow in the circuit is
blocked.

Types of Switch

 Single Pole Single Throw Switch (SPST)
 Single Pole Double Throw Switch (SPDT)
 Double Pole Single Throw Switch (DPST)
 Double Pole Double Throw Switch (DPDT)
 Push Button Switch.

 Toggle Switch.
 Limit Switch.
 Float Switches.

5. Loads - a source drives a load. Whatever component or peice or piece of equipment is
connected to a source and draws current from a source is a load on that source. ( this is one of
the materials)
 The following are examples but not limited to:
 Bulb
 Appliances

Source: https://kapitolyohs.files.wordpress.com/2011/06/terminating-and-connecting-of-electrical-
wirings-and-electronics-circuits-2nd.pdf

Quiz 1: IDENTIFICATION

Direction: Read and identify the following question and answer it on the space provided.

_________________1.This is a mechanical device used to connect and disconnect a circuit at will.
This covers a wide range of types, from sub-miniature up to industrial plant switching megawatts of
power on high voltage distribution lines.

_________________2. This is a single slender rod or filament of drawn metal. This definition
restricts the term to what would ordinarily be understood as solid wire.

_________________3. This is a safety device used to protect an electrical circuit from the effect of
excessive current. Its essential component is usually a strip of metal that will melt at a given
temperature.

_________________4.This is a source that drives a load. Whatever component or peice or piece
of equipment is connected to a source and draws current from a source

_________________5. When the power is running an electrical circuit moves charge with only one
direction .

ANSWER KEY OF IDENTIFICATION:

1. Switches
2. Wires
3. Fuse
4. Load
5. DC Source

Topic 2 Specific guidelines and procedures

Lesson 1 Guidelines and Procedures Safety

Electricity has become an essential part of our everyday life. It is used to power research
equipment, office equipment, heating and cooling equipment, etc. Electricity can be dangerous,
causing shocks, fires, explosions, or burns. Accidents involving electricity may cause minor injury
or may result in serious disabling injuries or death. Electricity must be recognized and respected as
a serious workplace hazard. Most injuries involving electricity could have been prevented if unsafe
equipment had been taken out of service or if unsafe work areas and work practices did not exist.
To minimize the risk of injury from electrical sources, it is necessary to assure that electrical
"sources" are properly insulated and grounded, that circuit-protecting devices are utilized, and that
safe work practices are followed.

Source:https://www.smu.edu/~/media/Site/BusinessFinance/OPRM/EHS/Documents/Electrical%20
Safety.ashx?la=en

2.2 Guidelines and Precaution

Electrical Safety - Basic Information

Why is it so important to work safely with or near electricity?
The voltage of the electricity and the available electrical current in regular businesses and homes
has enough power to cause death by electrocution. Even changing a light bulb without
unplugging the lamp can be hazardous because coming in contact with the "hot", "energized" or
"live" part of the socket could kill a person.

Source: https://www.ccohs.ca/oshanswers/safety_haz/electrical.html

What do I need to know about electricity?

All electrical systems have the potential to cause harm. Electricity can be either "static" or
"dynamic." Dynamic electricity is the uniform motion of electrons through a conductor (this is
known as electric current). Conductors are materials that allow the movement of electricity
through it. Most metals are conductors. The human body is also a conductor. This document is
about dynamic electricity.

Note: Static electricity is accumulation of charge on surfaces as a result of contact and
friction with another surface. This contact/friction causes an accumulation of electrons on one
surface, and a deficiency of electrons on the other surface. The OSH Answers document on
How Do I

Work Safely - Static Electricity has more information.
Electric current cannot exist without an unbroken path to and from the conductor. Electricity
will form a "path" or "loop". When you plug in a device (e.g., a power tool), the electricity
takes the easiest path from the plug-in, to the tool, and back to the power source. This action
is also known as creating or completing an electrical circuit.

Source: https://www.ccohs.ca/oshanswers/safety_haz/electrical.html

What kinds of injuries result from electrical currents?

People are injured when they become part of the electrical circuit. Humans are more
conductive than the earth (the ground we stand on) which means if there is no other easy
path, electricity will try to flow through our bodies.
There are four main types of injuries: electrocution (fatal), electric shock, burns, and falls.

These injuries can happen in various ways:

 Direct contact with exposed energized conductors or circuit parts. When electrical
current travels through our bodies, it can interfere with the normal electrical signals
between the brain and our muscles (e.g., heart may stop beating properly, breathing
may stop, or muscles may spasm).

 When the electricity arcs (jumps, or "arcs") from an exposed energized conductor or
circuit part (e.g., overhead power lines) through a gas (such as air) to a person who is
grounded (that would provide an alternative route to the ground for the electrical
current).

 Thermal burns include burns from heat generated by an electric arc, and flame burns
from materials that catch on fire from heating or ignition by electrical currents or an
electric arc flash. Contact burns from being shocked can burn internal tissues while
leaving only very small injuries on the outside of the skin.

 Thermal burns from the heat radiated from an electric arc flash. Ultraviolet (UV) and
infrared (IR) light emitted from the arc flash can also cause damage to the eyes.

 An arc blast can include a potential pressure wave released from an arc flash. This
wave can cause physical injuries, collapse your lungs, or create noise that can
damage hearing.

 Muscle contractions, or a startle reaction, can cause a person to fall from a ladder,
scaffold or aerial bucket. The fall can cause serious injuries.

Source: https://www.ccohs.ca/oshanswers/safety_haz/electrical.html

What should I do if I think I am too close to overhead power lines?

Do not work close to power lines. Recommended distances vary by jurisdiction and/or utility
companies. Check with both your jurisdiction and electrical utility company when working,
driving, parking, or storing materials closer than 15 m (49 feet) to overhead power lines.

 If you must be close to power lines, you must first call your electrical utility company
and they will assist you.

 If your vehicle comes into contact with a power line:
o DO NOT get out of your vehicle.
o Call 911 and your local utility service for help.
o Wait for the electrical utility to come and they will tell you when it is safe to get
out of your vehicle.
o Never try to rescue another person if you are not trained to do so.
o If you must leave the vehicle (e.g., your vehicle catches on fire), exit by jumping
as far as possible – at least 45 to 60 cm (1.5 to 2 feet). Never touch the vehicle
or equipment and the ground at the same time. Keep your feet, legs, and arms
close to your body.
o Keep your feet together (touching), and move away by shuffling your feet.
Never let your feet separate or you may be shocked or electrocuted.
o Shuffle at least 10 metres away from your vehicle before you take a normal
step.

 Do not enter an electrical power substation, or other marked areas.

Source: https://www.ccohs.ca/oshanswers/safety_haz/electrical.html

What are some general safety tips for working with or near electricity?

 Inspect portable cord-and-plug connected equipment, extension cords, power bars,
and electrical fittings for damage or wear before each use. Repair or replace damaged
equipment immediately.

 Always tape extension cords to walls or floors when necessary. Do not use nails and
staples because they can damage extension cords and cause fire and shocks.

 Use extension cords or equipment that is rated for the level of amperage or wattage
that you are using.

 Always use the correct size fuse. Replacing a fuse with one of a larger size can cause
excessive currents in the wiring and possibly start a fire.

 Be aware that unusually warm or hot outlets or cords may be a sign that unsafe wiring
conditions exist. Unplug any cords or extension cords from these outlets and do not
use until a qualified electrician has checked the wiring.

 Always use ladders made with non-conductive side rails (e.g., fibreglass) when
working with or near electricity or power lines.

 Place halogen lights away from combustible materials such as cloths or curtains.
Halogen lamps can become very hot and may be a fire hazard.

 Risk of electric shock is greater in areas that are wet or damp. Install Ground Fault
Circuit Interrupters (GFCIs) as they will interrupt the electrical circuit before a current
sufficient to cause death or serious injury occurs.

 Use a portable in-line Ground Fault Circuit Interrupter (GFCI) if you are not certain that
the receptacle you are plugging your extension cord into is GFCI protected.

 Make sure that exposed receptacle boxes are made of non-conductive materials.

 Know where the panel and circuit breakers are located in case of an emergency.

 Label all circuit breakers and fuse boxes clearly. Each switch should be positively
identified as to which outlet or appliance it is for.

 Do not use outlets or cords that have exposed wiring.

 Do not use portable cord-and-plug connected power tools if the guards are removed.

 Do not block access to panels and circuit breakers or fuse boxes.

 Do not touch a person or electrical apparatus in the event of an electrical incident.
Always disconnect the power source first.

Source: https://www.ccohs.ca/oshanswers/safety_haz/electrical.html

What is a sample checklist for basic electrical safety?
Inspect Cords and Plugs

 Check extension cords and plugs daily. Do not use, and discard corns and plugs if

they are worn or damaged.
 Have any extension cord that feels more than comfortably warm checked by an

electrician.

Source: https://www.ccohs.ca/oshanswers/safety_haz/electrical.html

Eliminate Octopus Connections

 Do not plug several items into one outlet.
 Pull the plug, not the cord.
 Do not disconnect power supply by pulling or jerking the cord from the outlet. Pulling the

cord causes wear and may cause a shock.

Source: https://www.ccohs.ca/oshanswers/safety_haz/electrical.html

Never Break OFF the Third Prong on a Plug

 Replace broken 3-prong plugs and make sure the third prong is properly grounded.

Source: https://www.ccohs.ca/oshanswers/safety_haz/electrical.html

Never Use Extension Cords as Permanent Wiring

 Use extension cords only to temporarily supply power to an area that does not have a
power outlet.

 Keep extension cords away from heat, water and oil. They can damage the insulation and
cause a shock.

 Do not allow vehicles to pass over unprotected extension cords. Extension cords should be
put in protective wireway, conduit, pipe or protected

Souce: https://www.ccohs.ca/oshanswers/safety_haz/electrical.html

Quiz 2: TRUE OR FALSE:

Direction: Write T if the statement is TRUE, Write F if the statement is FALSE.

_________1. The voltage of the electricity and the available electrical current in regular businesses
and homes has enough power to cause death by electrocution.

_________2. Check extension cords and plugs daily. Do not use, and discard corns and plugs if
they are worn or damaged.

_________3. It is not allowed to follow the manufacturer's instructions with respect to the use of a
GFCI.

_________4. Electricity can be either "static" or "dynamic."

_________5. Inspect portable cord-and-plug connected equipment, extension cords, power bars,
and electrical fittings for damage or wear before each use. Repair or replace damaged equipment
immediately.

_________6. You need to operate tools in an area containing explosive vapours or gases, unless
they are intrinsically safe and only if you follow the manufacturer's guidelines.

_________7. Do not use light duty extension cords in a non-residential situation.

_________8. Have any extension cord that feels more than comfortably warm checked by an

electrician.

_________9. Do not disconnect power supply by pulling or jerking the cord from the outlet. Pulling
the cord causes wear and may cause a shock.

_________10. Allow vehicles to pass over unprotected extension cords. Extension cords should
be put in protective wire way, conduit, pipe or protected

ANSWER KEY OF TRUE OR FALSE:

1. T
2. T
3. F
4. T
5. T
6. F
7. T
8. T
9. T
10. F

Prepared by:

Anna Marie D. Gime
EPAS – Trainer, BPTI