Lesson 2: Electrical Supplies and Material

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Overview

This lesson covers the knowledge, skills, and proper attitude in identifying, classifying, and selecting supplies and materials as per job requirement.

Learning Objectives

At the end of the lesson, you should be able to:

Cognitive Domain

Identify commonly used electrical supplies and materials.

Affective Domain

Prepare supplies and materials according to its uses on a specific project.

Psychomotor Domain

Choose appropriate electrical supplies and materials for specific job.

Watch the video and accomplished the tasks given!

Good Luck Future Electricians

Now it is time to show us what you have learned!

Read and follow the directions given below!

Learning Activity 1

Instruction: Answer the following questions that are given on the document provided and submit your answer through Google Drive Link below.

The File Name of your output shall always be in this suggested format:

SurnameFNMI_LearningActivityNo.

Example: HandayanRM_LA1

Submit or upload your output to the Google Drive Link. Click the button below:

Learning Activity 1

Module 1-Lesson 2 Activity Sheet.pdf

Learning Activity 2

Instruction: Answer the following questions that are given on the document provided and submit your answer through Google Drive Link below.

The File Name of your output shall always be in this suggested format:

SurnameFNMI_LearningActivityNo.

Example: DelaCruzJP_LA2

Submit or upload your output to the Google Drive Link. Click the button below:

Learning Activity 2

Module 1-Lesson 2 Activity Sheet.pdf

You did a great job! Now it's time to gain more knowledge about this lesson.

Read and Analyze the information given and perform the given activities below!

Module 1: Preparing Electrical Tools and Materials

Lesson 2: Electrical Supplies and Materials

Electrical materials are developed and constructed for a special purpose such as to:

1. Control the flow of current in an electrical circuit;

2. Carry electrical current from the source to the load or current consuming apparatus;

3. Hold and secure wires to its fixtures inside and outside houses and buildings; and

4. Protect the houses, buildings, appliances’ and instruments from any destruction and damage.

The following are the most commonly used electrical materials:

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Convenience Outlet

A device that acts as a convenient source of electrical energy for current consuming appliances. It is where the male plug of an appliance is inserted and usually fastened on the wall or connected in an extension cord. It maybe single, duplex, triplex or multiplex and could be surface type or flush type.

Male Plug

A device inserted to a convenience outlet to conduct electric current. A flat cord is attached to it on one end and the other end is connected to a current consuming instrument or appliance.

Lamp Holder

Devices that hold and protect the lamp and are also called as Lamp Sockets/Receptacles‖. These come in many designs and sizes. They are classified as flush, hanging (weather proof/chain) and surface types.

Switch

A device that connects and disconnects the flow of electric current in a circuit. There are many shapes, designs, and types and they are classified as hanging, flush, and surface types.

Fuse

A circuit protective device that automatically blows and cut the current when and over load or short circuit happens.

Junction Box

An octagonal shaped electrical material where the connections or joints of wires are being done. It is also where the flush type lamp holder is attached. This could be made of metal or plastic (PVC) Polyvinyl chloride.

Circuit Breaker

A protective device used to automatically blow and cuts the current when trouble in the circuit such as short circuit or overload occurs.

Utility Box

A rectangular shaped metallic or plastic (PVC) material in which flush type convenience outlet and switch are attached.

Flat Cord

Is a duplex stranded wire used for temporary wiring installation and commonly used in extension cord assembly. It comes in a roll of 150 meters and with sizes of gauge # 18 and gauge # 16 AWG (American wire gauge).

Electrical Wire/Conductor

Electrical material that could be:

a) Stranded wire which is made of multiple strands joined together to make a single wire.

b) Solid wire is made of a single strand of copper or Aluminum wire. These are used in wiring installation inside and outside the buildings.

Conduits/Pipe

Electrical materials used as the passage of wires for protection and insulation. These could be rigid metallic, flexible metallic conduit (FMC), rigid nonmetallic (PVC), and flexible non-metallic or corrugated plastic conduit (CPC).

Clamps

Electrical material that could be:

a) Stranded wire which is made of multiple strands joined together to make a single wire.

b) Solid wire is made of a single strand of copper or Aluminum wire. These are used in wiring installation inside and outside the buildings.

Connectors

Used to attach metallic or non-metallic conduit to the junction or utility boxes.

Types of Conduits

Rigid Metal Conduit- RMC

Is heavy-duty galvanized steel tubing that is installed with threaded fittings, it is typically used outdoors to provide protection from damage and can also provide structural support for electrical cables, panels, and other equipment. RMC is sold in 10- and 20-foot lengths and has threads on both ends.

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Intermediate Metal Conduit- IMC

Is a thinner, lighter-weight version of rigid metal conduit and is approved for use in all of the same applications as RMC. Because IMC is lighter and easier to work with than RMC, it is more common in new construction.

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Electrical Metal Tubing- EMT

Another example of a rigid electrical conduit is EMT (electrical metal tubing), which is most commonly made of galvanized steel but can also be Aluminum EMT is also called "thin-wall" conduit because it is thin and lightweight, especially compared to RMC. EMT is rigid but can be bent with a simple tool called a conduit bender.

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Intermediate Metal Conduit- IMC

Rigid polyvinyl chloride (PVC) is similar to plastic plumbing pipe and is installed with plastic fittings that are glued in place. It can be bent after being heated in a portable heater box.

Electrical Wires

Some factors that will affect your choice of electrical wiring include color, label information and applications. The information printed on the electrical wire covering is all that you need to choose the correct wire for your home.

Here’s some detailed information on the various features of electrical wire, which will help you choose the correct composition:

1. Size of Wires

Each application requires a certain wire size for installation, and the right size for a specific application is determined by the wire gauge. Sizing of wire is done by the American wire gauge system. Common wire sizes are 10, 12 and 14 – a higher number means a smaller wire size, and affects the amount of power it can carry. For example, a low-voltage lamp cord with 10 Amps will require 18-gauge wire, while service panels or subpanels with 100 Amps will require 2-gauge wire.

2. Wire Lettering

The letters THHN, THWN, THW and XHHN represent the main insulation types of individual wires. These letters depict the following NEC requirements:.

T – Thermoplastic insulation

H – Heat resistance

HH – High heat resistance (up to 194°F)

W – Suitable for wet locations

N – Nylon coating, resistant to damage by oil or gas

X – Synthetic polymer that is flame-resistant

3. Types of Electrical Wire

There are mainly 5 types of wire:

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.

Panel Feed Wires

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

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.

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Main Feed 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.

4. Color Codes

Different color wires serve different purposes, like:

· Black: Hot wire, for switches or outlets.

· White: Always neutral.

Circuit Breaker

Circuit breaker is an automatically operating safety switches which operate by measuring heat or current flowing through the circuit. If that exceeds a pre-set limit, they ‘trip’ and sever the electricity supply as quickly as possible. Unlike fuses, once the fault has been rectified, they don’t require replacing and can simply be reset.

Need for Circuit Breaker

Circuit breaker is an absolutely essential part of any electrical system. Used in conjunction with proper grounding, they can safeguard against electrocution. Circuit breaker also protect appliances, wiring and property against fire hazards and other damage resulting from abnormal current flow, short circuiting, overloading, and heat build-up.

Circuit Breaker Design and Components

Almost all circuit breakers have five basic components:

External Casing:

This is the external shell that encases the other parts. Based on the rated current and voltage, they are further divided into three types:

o Molded Case: Typically used in low voltage circuit breakers

o Insulated Case: Used in circuit breakers rated for medium voltage and amperage

Metal Clad: Generally for the higher end of the medium-rated circuit breakers

Electrical Contacts:

There are two contacts in a circuit breaker – a fixed contact and a floating contact (which is controlled by the circuit breaker). When the breaker trips, the floating contact moves away from the fixed contact and disconnects the electricity supply into the circuit.

Electrical Arc Extinguishing Mechanism:

When the contacts disconnect, electricity can jump through the gap between the last parts in contact. This creates an arc of electricity that can reach very high temperatures. To prevent damage and keep the arc from recreating itself, a circuit breaker uses an arc quenching mechanism to stop these arcs.

Main Operating Mechanisms:

Circuit breakers can use a variety of methods to disconnect power supply. These can include spring-loaded switches, solenoids, hydraulic and pneumatic switches.

Trip Elements:

Current flowing through a circuit creates heat and a magnetic field. Trip elements are calibrated to use either or both these factors to gauge the current and voltage and trip a switch, in case the maximum ratings are exceeded.

Types of Circuit Breaker

There are many types of circuit breaker designs and they can be classified on the basis of voltage (high, medium and low) or other characteristics like their arc quenching media and operating mechanism:

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Oil-Based Circuit Breaker

In oil-based circuit breakers, both the contacts are submerged in insulating mineral oil. When the breaker trips and the contacts disconnect, the resulting arc vaporizes the oil, which decomposes and forms a barrier of compressed hydrogen around the arc. This prevents further arcing after the circuit is broken.

Bulk oil circuit breakers use a larger volume of oil for both arc quenching and insulation, while minimum oil circuit breakers use smaller volumes of oil, only as an interruption medium.

Air Circuit Breaker

Can be used for low-voltage and some medium-voltage circuits too. They operate by increasing the arc voltage, which is the minimum voltage required to maintain an arc. Once it reaches a point greater than the supply voltage, the arc collapses.

These breakers are classified into two types -plain air and air blast. Depending on the design, they can achieve arc interruption by either cooling the arc plasma, increasing the length of the arc must travel, or splitting a single arc into multiple arcs.

Voltage Ratings

Each circuit breaker is designed to handle a certain range of voltage, so they can also be categorized on the basis of their voltage rating:

High Voltage Circuit Breaker:

While there isn’t a global standard, according to the International Electro-technical Commission (IEC), circuit breakers for controlling high-power transmission lines are rated for 72.5 KV and higher. Single-pole circuit breakers allow a single phase to be disconnected, which can improve stability and reduce overall failure time. High-voltage direct current (HVDC) circuit breakers are used to handle the power generated and fed from renewable sources.

These types of breakers usually use solenoid-operated or disconnecting circuit breakers, and because of the heavy loads, they incorporate sophisticated arc-quenching media like SF6 and CO2. Since safety is critical for higher voltage, high-voltage circuit breakers almost always use a variety of fail-safes, which include:

Current transformers with protective relays
Overload and ground fault protection
Enclosures that are kept at line potential (live tank) or earth potential (dead tank)

Medium Voltage (MV) Circuit Breaker:

Circuit breaker rated between 1 and 72 KV are categorized as medium-voltage circuit breakers. Lower rating breakers (like those for indoor use) are generally installed in metal-enclosed switch-gears, while larger ones that protect feeder lines from substations are individually installed as components.

Parameters for MV breakers are governed by international standards, like the IEC 62271, and almost always use protective relays and current sensors instead of thermal or magnetic breaking mechanisms. MV breakers can be further classified by their arc-quenching media:

Vacuum circuit breakers have rated currents over 6,300A and a voltage rating of up to 40.5KV. They generally last longer and require less maintenance.
Air circuit breakers are also rated for currents of 6,300A and over, though they often incorporate adjustable trip levels and delays. They’re often used in industrial applications for main power distribution.
SF6 circuit breakers have gained popularity over oil arc-quenching media because of growing environmental concerns over oil spills

Low Voltage Circuit Breaker:

LV breakers are used when the maximum voltage is about 1000Vac, and include miniature circuit breakers (MCB). They’re most often used in households and offices, and can be installed in tiers on a switchboard or a switchgear cabinet for easy access, resetting and replacement. Molded case circuit breakers use thermal or magnetic overload sensors and are available for ratings up to 2,500A.

Low-voltage circuit breakers are of three types:

Type B will trip when subjected to 3 to 5 times of the full load current
Type C can handle heavier loads, between 5 to 10 times of the full load current
Type D has the heaviest load handling capacity, between 10 and 20 times the full load current.

Electrical Connectors

What are Electrical Connectors?

Electrical circuits are composed of a multitude of components, including wires and cables. Electrical connectors are used to join these to form a continuous path for electrical current to flow. Connectors have male-ends (plugs) and female-ends (jacks) which connect to each other forming either a permanent connection or, more often, a temporary connection that can be assembled and removed with special tools.

Electrical connectors drastically reduce the time, effort and manpower needed for manufacturing, assembling and installing electrical devices, their components as well as wiring.

Composition

Most connectors have two main parts – the housing, and terminals for making the connections:

Housing – The housing is the structure or case used to contain the terminals, ensure stability of the connections and protect the electrical contacts from short-circuiting and environmental hazards. Connector housings are normally made of molded plastic, but other insulating materials like ceramics are also used.
Terminals – Terminals are the pins in a connector which provide electrical conduction to make the connections secure. They are almost always composed of a metal, but some of them use other conductive

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Plug and Receptacles

The term “plug” refers to an electrical device that supplies electrical current from receptacles to the electronic devices. All the electrical appliances, machines and other devices depend on these plugs and receptacles for their powering needs. When wiring a house or a commercial place or when conducting repairs, it is imperative to have a clear understanding about plugs and receptacles in general and a few other things related to them as well.

Motor Controls

Motor controls can ideally be identified as a group of devices that govern the performance of an electric motor in a predefined manner. Motor controls are also known as motor controllers. They have several essential functions which include: automatically or manually starting as well as stopping the operation of an electric motor, setting forward or reversing the course of rotation, selecting and regulating the speed of rotation, controlling or regulating the torque, as well as protecting the motor against several degrees of electrical overloads and faults.

Electric motors, regardless of their type, have a controller of some type. These motor controllers might differ in terms of their features and complexity, which is mainly determined by the function of a specific motor. The simplest example of a motor control mechanism is a regular switch that connects a motor to its power source. This switch can be a manual controller, or a relay connected to an automatic sensor for starting and stopping a motor.

Different Types of Motor Controller

Motor control devices are designed to be controlled in a manual, automatic, or remote manner. They can be used for starting or stopping a motor attached to a machine as well as served several other purposes. These controls are categorized according to the type of motor they are designed to operate.

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Motor Starters

Small motors can be started by simply plugging the electric switch into the receptacle and switching the power button on. However, larger motors need motor starters, or contractors, which are specialized switching units used to power an electric motor. On being powered, the direct on-line starters connect motor terminals to the power supply immediately. A reverse starter, which contains two direct on-line circuits, can also be used for rotating the motor in either direction. Very large motors that operate on medium voltage power supplies use power-circuit breakers as starter elements.

Reduced Voltage Starters

Two or more starters are used for starting a motor in reduced voltage conditions. Through a series of inductance or an autotransformer, lower voltage is presented at the motor terminals, which, in turn, helps in reducing the starting torque and the inrush electric current. Once the motor reaches a certain fraction of its top-load speed, the starter automatically transfers full voltage current to the motor terminals.

Servo Motor Controller

Servo controllers can be understood as a wide category of motor control devices, primarily known for their highlighting features like:

Precise closed-loop positional control.
Fast rate acceleration.
Precise speed control servo motors made from different types of motors, including AC servo motors, brushed DC motors and brush-less DC motors.

These controls use position feedback for closing the control loop and are commonly used in combination with re-solvers, encoders, and Hall Effect sensors for directly measuring the position of rotors.