US Army Engineer Course - Electricity VI (Install Convenience Devices) EN5145

69 Pages·2021·1.75 MB·English

SUBCOURSE
EDITION

EN5145
B

US ARMY ENGINEER SCHOOL

INSTALL CONVENIENCE DEVICES

INSTALL CONVENIENCE DEVICES

Subcourse Number EN 5145

EDITION B

United States Army Engineer School
Fort Leonard Wood, Missouri 65473

3 Credit Hours

Edition Date: October 1999

SUBCOURSE OVERVIEW

This subcourse is designed to teach the knowledge necessary to describe the types and installation
procedures of switches, receptacles, and incandescent and fluorescent lighting fixtures. This subcourse
contains three lessons, each corresponding to a terminal learning objective as indicated below.

There are no prerequisites for this subcourse.

This subcourse reflects the doctrine which was current at the time it was prepared. In your own work
situation, always refer to the latest official publications.

Appendix A contains a metric conversion chart.

Unless otherwise stated, the masculine gender of singular pronouns is used to refer to both men and
women.

TERMINAL LEARNING OBJECTIVE

ACTION:
You will learn to describe the types of switches, receptacles, and incandescent and
fluorescent lighting fixtures and their installation procedures.

CONDITION:
You will be given the material in this subcourse, and an Army Correspondence
Course Program (ACCP) examination response sheet.

STANDARD:
To demonstrate competency of this task, you must achieve a minimum of 70 percent
on the subcourse examination.

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TABLE OF CONTENTS

Section
Page

Subcourse Overview.................................................................................................................................i

Administrative Instructions ..................................................................................................................iv

Grading and Certification Instructions .................................................................................................iv

Lesson 1: Switches...............................................................................................................................1-1

Part A: Basic Switches ............................................................................................................1-2

Part B: Installing Basic Switches..............................................................................................1-4

Part C: Types of Switches.......................................................................................................1-7

Practice Exercise....................................................................................................................1-17

Answer Key and Feedback....................................................................................................1-19

Lesson 2: Receptacles..........................................................................................................................2-1

Part A: Basic Receptacles .......................................................................................................2-2

Part B: Special-Use Outlets......................................................................................................2-6

Part C: Power Outlets..............................................................................................................2-8

Part D: Miscellaneous Receptacles.........................................................................................2-11

Practice Exercise....................................................................................................................2-13

Answer Key and Feedback ...................................................................................................2-14

Lesson 3: Lighting Fixtures ................................................................................................................3-1

Part A: Basic Incandescent Light Fixtures .............................................................................3-2

Part B: Basic Fluorescent Light Fixtures..................................................................................3-9

Practice Exercise....................................................................................................................3-20

Answer Key and Feedback ...................................................................................................3-21

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Appendix A: Metric Conversion Chart .............................................................................................A-1

Appendix B: List of Common Acronyms...........................................................................................B-1

Appendix C: Recommended Reading List ........................................................................................C-1

Student Inquiry Sheets

Important: Electronic Examination Information

This paper subcourse does not contain the examination. The examination response sheet is included
only as a mailing label. You must go to the following web site to complete the examination and submit
it for grading.

http://www.aimsrdl.atsc.army.mil/accp/accp_top.htm

Registered students (those with ACCP userids and passwords) should key in the userid and password to
LOGON, then click on the EXAM button to access the examination.

Students who have not yet registered should click on the REGISTER button on the lower right corner of
the screen. Follow directions to create a userid and password. Then click on the EXAM button to
access the examination.

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ADMINISTRATIVE INSTRUCTIONS

1.
Number of lessons in this subcourse: Three.

2.
Materials you need in addition to this booklet are a number (No.) 2 pencil and the ACCP

examination response sheet and the preaddressed envelope you received with this subcourse.

3.
Supervisory requirements: None.

4.
References: The following publications provide additional information about the material in this

subcourse. You do not need these materials to complete this subcourse.

•
FM 5-424. Theater of Operations Electrical Systems. 25 June 1997.

•
Soldier Training Publication (STP) 5-51R12-SM-TG. Soldier's Manual and Trainer's Guide,
MOS 51R, Interior Electrician, Skill Levels 1/2. 27 October 1988.

•
1999 National Electrical Code® (NEC®), available from the--

National Fire Protection Association
1 Batterymarch Park
Quincy, Massachusetts 02269-9101

GRADING AND CERTIFICATION INSTRUCTIONS

Examination: This subcourse contains a multiple-choice examination covering the material in the three
lessons. After studying the lessons and working through the practice exercises, complete the
examination. Mark your answers in the subcourse booklet, and then transfer them to the ACCP
examination response sheet. Completely black out the lettered oval which corresponds to your selection
(A, B, C, or D). Use a No. 2 lead pencil to mark your responses. When you complete the ACCP
examination response sheet, mail it in the preaddressed envelope you received with this subcourse. You
will receive an examination score in the mail. You will receive three credit hours for successful
completion of this examination.

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LESSON 1

SWITCHES

Critical Task: 051-246-1112

OVERVIEW

LESSON DESCRIPTION:

In this lesson, you will learn to describe the types of switches and their installation procedures.

TERMINAL LEARNING OBJECTIVE:

ACTION:
You will learn to describe the types of switches and their installation procedures.

CONDITION:
You will be given the material contained in this lesson.

STANDARD:
You will correctly answer practice exercise questions at the end of this lesson.

REFERENCES:
The material contained in this lesson was derived from STP 5-51R12-SM-TG, FM 5-
424, and the National Electrical Code (NEC).

INTRODUCTION

This lesson, part of the military occupational specialty (MOS) 51R Skill Levels 1 and 2 course, provides
the knowledge necessary to identify and install the various types of electrical switches.

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PART A: BASIC SWITCHES

The electrical device itself (color, shape, and printed words) provides important installation information
(Figure 1-1).

Figure 1-1. Electrical switches

The UL stamp (Figure 1-2) means that the Underwriters' Laboratories, Inc. (UL) has tested the device
and found it safe for use.

Figure 1-2. Safety tested stamp

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Switches are now manufactured with green grounding screws attached. This will allow for the circuit
and the switch to be grounded without using a metal box (Figure 1-3).

Figure 1-3. Green ground screw found on most new switches

Devices may have the initials "CU/AL" imprinted on them (Figure 1-4). This means the device is
approved for copper and aluminum conductors. However, due to a change in the NEC, aluminum
conductors cannot be used for interior branch circuits. They are only approved for service-entrance
installations.

Figure 1-4. Approved conductors

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The proper wiring of a circuit is one of the most important factors for installing a device. The NEC
color code must be followed. Single-pole switches are not color-coded; both screws will be the same
color.

PART B: INSTALLING BASIC SWITCHES

Plaster ears on a device keep it even with the mounted surface. They help keep the switch flat against
the wall, even if the box is crooked. The ears can be broken off when not needed (Figure 1-5).

Figure 1-5. Plaster ears

The elongated slot in the device's mounting bracket is designed to align the switch vertically. This will
allow you to make the switch straight even when the box is not straight (Figure 1-6).

Figure 1-6. Elongated slot

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Switches come with mounting screws already attached. They are held in place with fiber washers
(Figure 1-7).

Figure 1-7. Mounting screws

Many devices have wiring holes to speed up the installation of conductors. This procedure is called back
feeding or back wiring. When troubleshooting, examine the wiring holes for loose or poor connections.
Wiring holes are used with solid wire only; good connections are not made with stranded wires. The
electrical equipment being installed determines the size of the wire/conductor that can be back fed.
Regardless of what the equipment recommends, never force a conductor into a device (Figure 1-8).

Figure 1-8. Wiring holes

The strip gauge is an installation guide found on the back of some devices. It shows how much
insulation should be removed from the conductors. The strip gauge is normally between 1/2 and 3/4
inch long. The length depends on the type of device and the manufacturer.

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When back feeding, remember to check the length of the strip gauge. Make sure that you remove the
proper amount of insulation from the conductor to make a good connection with the device (Figure 1-9).

Figure 1-9. Strip gauge

If back feeding cannot be accomplished, screw loops must be used. To make screw loops, remove
approximately 5/8 inch of insulation from the conductor. Grip the end of the conductor with needle-
nose pliers, and bend the conductor to form a loop. When the conductor is placed around a screw, it
must wrap in the direction the screw turns to tighten. This will cause the screw to pull the conductor in
tight when the screw is tightened (Figure 1-10).

Figure 1-10. Screw loops

All electrical devices are marked with voltage and amperage ratings. Wattage, amperage, and voltage are
all in direct relation to each other. To determine the wattage, use the formula voltage x amperage =
wattage. Thus, to figure voltage, use the formula wattage divided by amperage = voltage. An easy way to
remember this is to use the chart shown in Figure 1-11.

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To use this chart, insert the values you know and perform the mathematic calculation that is depicted.
Example: A light uses 60 watts at 120 volts. How many amperes (amps) is it using? Insert the amounts
for watts and volts. To get amps, you divide 60 by 120 and the answer is 0.5.

Figure 1-11. Pie chart

PART C: TYPES OF SWITCHES

Switches are made in assorted sizes and shapes and are rated at different voltages and amperages. A
single-pole switch is the most commonly used type of switch. Single-pole switches are used to control
devices, such as lights or receptacles, from one location (Figure 1-12).

Figure 1-12. Single-pole switch

There are simple rules of thumb, that when followed, make wiring circuits very easy. Here are the rules
of thumb for a single-pole switch:

Rule 1: The hot conductor (wire) is the only conductor that is switched. The incoming hot

conductor from the power source goes to either terminal on the switch.

Rule 2: The conductor going from the other terminal of the switch goes to the device. This

conductor must be black.

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Rule 3: The neutral conductor goes to the current-using device (such as a receptacle or a light

fixture), and it must be white or neutral gray.

There are two wiring methods that the electrician must know. The first is an "in line," and the

second is a "switch loop." If the conductors from the panel box go to the switch then to the light, it is
an in-line circuit. Follow the rules of thumb and compare them with Figure 1-13 below.

Figure 1-13. In-line circuit

A switch loop occurs when the conductors go to the light then to the switch. In Figure 1-14 notice that
the same rules of thumb were used for both wiring methods.

Figure 1-14. Switch-loop circuit

In the switch loop (Figure 1-14), the incoming black (hot) conductor is spliced to a white conductor
(making it a hot conductor) at the light to complete the run to the switch.

When a white conductor is used to carry current to a switch, as in a switch loop, the white conductor
must be permanently marked to indicate it is not neutral but is now a hot conductor. This is usually
done with black electrician's tape. Place a piece of tape at both ends of the white conductor that is
being used as a hot conductor everywhere it is exposed in every box. Do not tape a white conductor
that is being used as a neutral conductor.

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When an electrical device requires control from two different locations (for example, the top and bottom
of stairs), three-way switches are used. Three-way switches must be used in pairs. Three-way switches
have three terminals or screws on them and no ON or OFF markings on the handle (Figure 1-15).

Figure 1-15. Three-way switch

A three-way switch has three terminals, one common in brass or black and two travelers in silver, white,
or a light-colored metal. If all terminals are the same in appearance, there may be a letter beside the
common terminal (Figure 1-16).

Figure 1-16. Three-way switch with three terminals

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A three-way switch shift's the electrical path from the common terminal to one of the traveler terminals
(Figure 1-17).

NOTE: The terminal with a "C" beside it will be the common in this lesson; however, it may or may
not be marked with a "C" on an actual switch.

Figure 1-17. Three-way switch shifting the electrical path

When installing three-way switches, the silver screws on one three-way switch are wired together with
the silver screws on the other three-way switch, using conductors called travelers (Figure 1-18).

Figure 1-18. Traveler conductors

NOTE: As seen in Figure 1-18 a three-conductor cable is installed between three-way switches. A
three-conductor cable has a black, a white, and a red conductor in a protective outer sheathing.

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