US Army Engineer Course - Electricity I (Prepare an Electrical Materials Takeoff List) EN5140

8/4/2019 US Army Engineer Course - Electricity I (Prepare an Electrical Materials Takeoff List) EN5140

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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 SchoolFort 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 yourown work, always refer to the latest official publications.

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

TERMINAL LEARNING OBJECTIVE:

ACTION: You will learn to identify electrical symbols; extract information from an electricalprint 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 70percent 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. 2pencil 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 inthe mail. You will receive two credit hours for successful completion of this examination.

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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 legendand prepare an electrical MTOL.

CONDITION: You will be given the material contained in this lesson. You will work at your ownpace 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 mustknow 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, showstheir 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 theletter "S" and then further identified by an additional letter or number. The symbols used in thissubcourse are those most applicable to military use. Figure 3, page 4, shows electrical symbols in switchoutlets; 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 commonequipment 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 mayhave more than one meaning. Figure 7 shows symbols in general outlets; Figure 8, page 6, shows theircommon 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 itscompleteness and correctness. Each print has areas known as the legend and the diagram. The legendcontains detailed and general information as well as the scale of the print. The diagram containselectrical 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 severalmeanings, either one switch controls all the lights on the circuit, one switch controls all the lights in oneroom, or one switch controls all the lights in both rooms. Any questions or problems with prints shouldbe 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 orrun. Once isolated, follow the entire circuit, checking for errors. Continue this process until all circuitsare checked.

c. Refer to Figure 10. Begin with circuit A1, indicated by the small home-run arrow, and followthe line in the opposite direction to the end of the circuit. Circuit A1 is missing switches for the sixlights 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 printsbefore 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 theelectrical print. The schedule of drawings, as shown in Table 1, is the part of the legend that identifiesall 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 scaleequals 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 aproject. Numbers are used to represent each piece of equipment. These numbers are then placed on theprint 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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b. Electrical notes (Table 3) list specific instructions on special wiring requirements andequipment use.

Table 3. Electrical notes

c. The electrical legend (Figure 12) lists the interpretations for various electrical systems on theprint. Since some electrical symbols have more than one meaning, the electrician can refer to the legend

ad determine what device to install.

Figure 12. Electrical symbols in the legend

d. The panelboard schedule (Table 4, page 12) contains information such a wire size, circuitnumber, breaker size, load per circuit, and service entrance (SE) requirements, including demand andconnected load.

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Table 4. Panelboard schedule

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e. The wiring diagram (Figure 13) uses symbols to show the location of fixtures and devices inthe electrical system.

Figure 13. Wiring diagram

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PART D: LIST OF ELECTRICAL MATERIALS

6. The first task in an electrical job is to prepare an electrical MTOL. To do this, you must knowhow to extract information from the wiring diagram and legend. To determine installation needs forbranch circuits, look for items such as switch types, receptacles, lighting fixtures, cable, conductors, andconduit.

7. The wiring diagram and legend are necessary to correctly identify symbols and understand wiringrequirements. Using the wiring diagram (Figure 13, page 13), electrical notes (Table 3, page 11), and thepanelboard schedule (Table 4, page 12), compile an MTOL as shown in Table 5. Begin this task byidentifying the wires needed for branch circuits.

a. The size and type of conductors are not always shown in the wiring diagram. Thisinformation may also be found in the electrical notes or the panelboard schedule. Item 3 on theelectrical notes states that branch circuit conductors should be No. 12. This means that all wiring shouldbe 12/2 or 12/3 nonmetallic (NM), nonmetallic corrosive (NMC)(corrosion-resistant), or undergroundfeeder (UF) cable unless otherwise indicated; however, the panelboard schedule shows that circuits E4,ES, and E7 require 10-gauge conductors. When preparing an MTOL, look at each circuit individually

and determine what is needed to install each. In this example, circuit E7 requires 10-gauge, three-wireconductors to complete. Item 2 in the electrical notes states that if a conductor is size No. 2 or smaller,NM, NMC, or UF cable will be used. Begin the MTOL as shown in step 1.

b. A special-purpose outlet is needed on circuit E7. Add to the MTOL as shown at step 2. Thepanelboard schedule shows that circuit E7 requires a 30-amp, three-pole circuit breaker. Add thisinformation to the MTOL as shown at step 3.

c. Locate circuit E8 on Figure 13, page 13. The wire gauge is not listed on the print, so youmust look at the panelboard schedule. The panelboard schedule shows that circuit E8 requires 12-gaugeconductors. Add this information to the MTOL as shown in step 4.

d. Follow the line representing circuit E8. There are 4 fluorescent and 11 incandescent lightingfixtures listed in this circuit. Add this information to the MTOL as shown in steps 5 and 6.

e. Two three-way switches are shown in circuit E8. Add them to the MTOL as shown in step7.

f. Three-wire conductors are shown in circuit E8. Remember from the electrical notes (Table3, page 11) that NM, NMC, or UF cable is used on two- or three-cable branch circuits. Add this entryto the MTOL as shown in step 8.

g. Make sure that you check the entire circuit. Circuit E8 continues on the right side of Figure13. Twelve-gauge thermal/heat/water (TEW) conductors and 1/2-inch conduit are required. Add theseitems to the MTOL as shown in step 9.

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NOTE: If you feel that there is a better way to run a circuit than that listed on the diagram, discuss

alternatives with your supervisor.

h. Refer to the panelboard schedule for the type of breaker required in circuit E8. Thepanelboard schedule shows a three-pole, 20-amp breaker. Add this entry to the MTOL as shown in step10.

i. To complete the MTOL, repeat the procedures shown for circuits E7 and E8 on all remainingcircuits.

NOTE: Do not list supply items on the MTOL. Items such as staples, straps, boxes, and wire nuts

will be calculated and ordered on the BOM.

Table 5. Electrical MTOL

PART E: SERVICE-ENTRANCE REQUIREMENTS

8. Continue to refer to the wiring diagram (Figure 13, page 13), electrical notes (Table 3, page 11),

and panelboard schedule (Table 4, page 12) to add the SE requirements to the MTOL (Table 5, page 15).

a. Item 1 on the electrical notes status that the SE conductors should be type THW single-conductor copper cables, in heavy, wall, galvanized-steel conduit. Panelboard E shows that we needphase 3, four-wire conductors, run in 1 1/2-inch conduit. Add both of these entries to the MTOL asshown at step 11.

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b. Panelboard E also requires a 100-amp main breaker and room for at least 10 branch circuitbreakers. Add this item to the MTOL as shown at step 12.

9. Grounding requirements, which vary from state to state and county to county, are not listed on theMTOL. Electricians should be familiar with local codes for grounding and take the codes intoconsideration before ordering grounding materials and equipment. Order grounding materials whenpreparing the BOM.

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LESSON

PRACTICE EXERCISE

The following items will test your grasp of the material covered in this lesson. There is only one correctanswer for each item. When you complete the exercise, check your answer with the key that follows. If

you answer any item incorrectly, study again that part which contains the portion involved.

1. Match the symbols with the correct definition by placing the correct number in the blank provided.

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2. Refer to Figure 14. What materials are needed to install circuit A6?

Figure 14. Sample wiring diagram No. 1

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3. Refer to Figure 15. Identify one major error in circuits A1 and A2.


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4. Refer to Figure 16. What type of lighting fixture is called for in circuit D15?

A. WeathertightB. IncandescentC. FluorescentD. Explosion proof


5. Refer to Figure 16. List the types of switches, outlets, and conductors needed in circuit D15.

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LESSON

PRACTICE EXERCISE

ANSWER KEY AND FEEDBACK

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US Army Engineer Course - Electricity I (Prepare an Electrical Materials Takeoff List) EN5140

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