US Army Engineer Course - Electricity I (Prepare An Electrical Materials Takeoff List) En5140

27 Pages·2021·1.2 MB·English

SUBCOURSE
EDITION

EN5140
B

UNITED STATES ARMY ENGINEER SCHOOL

PREPARE AN ELECTRICAL-MATERIALS

TAKEOFF LIST

(ELECTRICITY I)

PREPARE AN ELECTRICAL-MATERIALS TAKEOFF LIST

(ELECTRICITY I)

Subcourse EN 5140

EDITION B

United State (US) Army Engineer School

Fort Leonard Wood, Missouri 65473

2 Credit Hours

Edition Date: September 1999

SUBCOURSE OVERVIEW

This subcourse is designed to teach the student the identification of electrical symbols, the use of
electrical materials, and the skills necessary to extract information from a electrical print and legend.

There are no prerequisites for this subcourse.

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

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 identify electrical symbols; extract information from an electrical
print and legend; and list electrical materials by type, size, and amount.

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

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

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TABLE OF CONTENTS

Section
Page

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

Administrative Instructions .......................................................................................................................iii

Grading and Certification Instructions.......................................................................................................iii

Lesson: Prepare an Electrical-Materials Takeoff List.,...............................................................................1

Part A: Electrical-Symbol Identification .............................................................................................2

Part B: Print Verification ....................................................................................................................6

Part C: Print Legends .........................................................................................................................8

Part D: List of Electrical Materials ...................................................................................................14

Part E: Service-Entrance Requirements ............................................................................................15

Practice Exercise ................................................................................................................................17

Answer Key and Feedback..................................................................................................................22

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

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

Appendix C: Metric Conversation Chart ..............................................................................................C-1

Student Inquiry Sheets

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GRADING AND CERTIFICATION INSTRUCTIONS

Examination: This subcourse contains a multiple-choice examination covering the material in the lesson.
After studying the lesson and working through the practice exercise, complete the examination. Mark
your answers in the subcourse booklet, 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
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 two credit hours for successful completion of this examination.

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THIS PAGE IS INTENTIONALLY LEFT BLANK.

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LESSON

PREPARE AN ELECTRICAL-MATERIALS TAKEOFF LIST

Critical Task: 051-246-1101

OVERVIEW

LESSON DESCRIPTION:

In this lesson, you will learn to identify electrical symbols, interpret electrical prints, use print legends,
and prepare an electrical-materials takeoff list (MTOL).

TERMINAL LEARNING OBJECTIVE:

ACTION:
You will learn to identify and extract information from an electrical print and legend
and prepare an electrical MTOL.

CONDITION:
You will be given the material contained in this lesson. You will work at your own
pace and in your own selected environment with no supervision.

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

REFERENCES:
The material contained in this lesson was derived from FM 5-424, STP 5-51R12-SM-
TG, TM 5-303, and TM 5-704.

INTRODUCTION

Before beginning an electrical job, materials must be ordered. Materials are ordered on a bill of
materials (BOM). The BOM is based on the MTOL. In order to prepare an electrical MTOL, you must
know how to identify electrical symbols and extract information from an electrical print and legend.

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PART A: ELECTRICAL-SYMBOL IDENTIFICATION

1.
Electrical symbols are divided into four areas: panels and circuits, switches, convenience outlets,

and general outlet.

a. Figure 1 shows electrical symbols used in panel and circuit outlets; Figure 2, page 3, shows

their common equipment use.

Figure 1. Electrical symbols in panel and circuit outlets

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Figure 2. Equipment with panel and circuit outlets

b. There are about 20 different switch symbols. Switches are generally characterized by the

letter "S" and then further identified by an additional letter or number. The symbols used in this
subcourse are those most applicable to military use. Figure 3, page 4, shows electrical symbols in switch
outlets; Figure 4, page 4 shows their common equipment use.

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Figure 3. Electrical symbols in switch outlets

Figure 4. Equipment with switch outlets

c. Figure 5 shows electrical symbols in convenience outlets; Figure 6 shows their common

equipment use.

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Figure 5. Convenience outlet symbols

Figure 6. Equipment with convenience outlets

d. General outlets have the widest variety of symbols. In some cases, the same symbol may

have more than one meaning. Figure 7 shows symbols in general outlets; Figure 8, page 6, shows their
common equipment use.

Figure 7. Electrical symbols in general outlets

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Figure 8. Equipment with general outlets

PART B: PRINT VERIFICATION

2.
Electricians must be able to read and understand an electrical print in order to verify its

completeness and correctness. Each print has areas known as the legend and the diagram. The legend
contains detailed and general information as well as the scale of the print. The diagram contains
electrical symbols ad indicates where each device is to be installed.

a. Figure 9 is an incomplete print of an electrical-wiring diagram. In the upper left corner of

circuit D15, one switch is shown. Several switches are needed for this circuit. This could have several
meanings, either one switch controls all the lights on the circuit, one switch controls all the lights in one
room, or one switch controls all the lights in both rooms. Any questions or problems with prints should
be addressed immediately to avoid project delays.

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Figure 9. Incomplete print of an electrical-wiring diagram

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b. One method of performing a complete check of a print is to isolate an individual circuit or

run. Once isolated, follow the entire circuit, checking for errors. Continue this process until all circuits
are checked.

c. Refer to Figure 10. Begin with circuit A1, indicated by the small home-run arrow, and follow

the line in the opposite direction to the end of the circuit. Circuit A1 is missing switches for the six
lights in the large room and the light in the small room. It is also missing a junction box where circuits
A1 and A2 join. The electrician should resolve any questions or misunderstandings about the prints
before ordering the materials or beginning the work.

Figure 10. Isolated circuit

PART C: PRINT LEGENDS

3.
General information is found in the legend. The legend is located in the lower, right corner of the

electrical print. The schedule of drawings, as shown in Table 1, is the part of the legend that identifies
all the drawings by number, gives the description of each, and lists the number of sheets per drawing.
The general notes also provide additional information, but normally this information pertains to the
overall electrical project rather than individual circuits.

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Table 1. Print legend

4.
The print scale can be either graphic or ratio (Figure 11). Each segment of line in the graphic scale

equals 1 foot of actual space; on a ratio scale, 1/8 inch equals 1 foot of actual space.

Figure 11. Print scale

5.
Additional instructions are found on the schedule of equipment, electrical notes, electrical legend,

and panelboard schedule.

a. The schedule of equipment (Table 2, page 10) lists the equipment needed to complete a

project. Numbers are used to represent each piece of equipment. These numbers are then placed on the
print where the equipment is to be used. The schedule of equipment also lists the horsepower of
motors, phase, and quantity of each equipment type, depending on the size of the structure.

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NOTE: To allow for easier reading, some item numbers shown in Table 2 have been removed from
Figure 9, page 7.

Table 2. Schedule of equipment

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