Neets v04-conductors

NONRESIDENT
TRAINING
COURSE
SEPTEMBER 1998

Navy Electricity and
Electronics Training Series
Module 4—Introduction to Electrical
Conductors, Wiring Techniques, and
Schematic Reading
NAVEDTRA 14176

DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.

Although the words “he,” “him,” and
“his” are used sparingly in this course to
enhance communication, they are not
intended to be gender driven or to affront or
discriminate against anyone.

DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.

PREFACE
By enrolling in this self-study course, you have demonstrated a desire to improve yourself and the Navy.
Remember, however, this self-study course is only one part of the total Navy training program. Practical
experience, schools, selected reading, and your desire to succeed are also necessary to successfully round
out a fully meaningful training program.

COURSE OVERVIEW: To introduce the student to the subject of Electrical Conductors, Wiring
Techniques, and Schematic Reading who needs such a background in accomplishing daily work and/or in
preparing for further study.

THE COURSE: This self-study course is organized into subject matter areas, each containing learning
objectives to help you determine what you should learn along with text and illustrations to help you
understand the information. The subject matter reflects day-to-day requirements and experiences of
personnel in the rating or skill area. It also reflects guidance provided by Enlisted Community Managers
(ECMs) and other senior personnel, technical references, instructions, etc., and either the occupational or
naval standards, which are listed in the Manual of Navy Enlisted Manpower Personnel Classifications
and Occupational Standards, NAVPERS 18068.

THE QUESTIONS: The questions that appear in this course are designed to help you understand the
material in the text.

VALUE: In completing this course, you will improve your military and professional knowledge.
Importantly, it can also help you study for the Navy-wide advancement in rate examination. If you are
studying and discover a reference in the text to another publication for further information, look it up.

1998 Edition Prepared by
AECS Steve Heartsfield

Published by
NAVAL EDUCATION AND TRAINING
PROFESSIONAL DEVELOPMENT
AND TECHNOLOGY CENTER

NAVSUP Logistics Tracking Number
0504-LP-026-8290

i

Sailor’s Creed

“I am a United States Sailor.

I will support and defend the
Constitution of the United States of
America and I will obey the orders
of those appointed over me.

I represent the fighting spirit of the
Navy and those who have gone
before me to defend freedom and
democracy around the world.

I proudly serve my country’s Navy
combat team with honor, courage
and commitment.

I am committed to excellence and
the fair treatment of all.”

ii

TABLE OF CONTENTS

CHAPTER PAGE

1. Electrical Conductors ............................................................................................... 1-1

2. Wiring Techniques ................................................................................................... 2-1

3. Schematic Reading ................................................................................................... 3-1

APPENDIX

I. Glossary.................................................................................................................. AI-1

II. Electrical and electronic Symbols .......................................................................... AII-1

III. References Used to Develop The Training Manual ............................................... AIII-1

INDEX ......................................................................................................................... INDEX-1

iii

NAVY ELECTRICITY AND ELECTRONICS TRAINING
SERIES
The Navy Electricity and Electronics Training Series (NEETS) was developed for use by personnel in
many electrical- and electronic-related Navy ratings. Written by, and with the advice of, senior
technicians in these ratings, this series provides beginners with fundamental electrical and electronic
concepts through self-study. The presentation of this series is not oriented to any specific rating structure,
but is divided into modules containing related information organized into traditional paths of instruction.

The series is designed to give small amounts of information that can be easily digested before advancing
further into the more complex material. For a student just becoming acquainted with electricity or
electronics, it is highly recommended that the modules be studied in their suggested sequence. While
there is a listing of NEETS by module title, the following brief descriptions give a quick overview of how
the individual modules flow together.

Module 1, Introduction to Matter, Energy, and Direct Current, introduces the course with a short history
of electricity and electronics and proceeds into the characteristics of matter, energy, and direct current
(dc). It also describes some of the general safety precautions and first-aid procedures that should be
common knowledge for a person working in the field of electricity. Related safety hints are located
throughout the rest of the series, as well.

Module 2, Introduction to Alternating Current and Transformers, is an introduction to alternating current
(ac) and transformers, including basic ac theory and fundamentals of electromagnetism, inductance,
capacitance, impedance, and transformers.

Module 3, Introduction to Circuit Protection, Control, and Measurement, encompasses circuit breakers,
fuses, and current limiters used in circuit protection, as well as the theory and use of meters as electrical
measuring devices.

Module 4, Introduction to Electrical Conductors, Wiring Techniques, and Schematic Reading, presents
conductor usage, insulation used as wire covering, splicing, termination of wiring, soldering, and reading
electrical wiring diagrams.

Module 5, Introduction to Generators and Motors, is an introduction to generators and motors, and
covers the uses of ac and dc generators and motors in the conversion of electrical and mechanical
energies.

Module 6, Introduction to Electronic Emission, Tubes, and Power Supplies, ties the first five modules
together in an introduction to vacuum tubes and vacuum-tube power supplies.

Module 7, Introduction to Solid-State Devices and Power Supplies, is similar to module 6, but it is in
reference to solid-state devices.

Module 8, Introduction to Amplifiers, covers amplifiers.

Module 9, Introduction to Wave-Generation and Wave-Shaping Circuits, discusses wave generation and
wave-shaping circuits.

Module 10, Introduction to Wave Propagation, Transmission Lines, and Antennas, presents the
characteristics of wave propagation, transmission lines, and antennas.

iv

Module 11, Microwave Principles, explains microwave oscillators, amplifiers, and waveguides.

Module 12, Modulation Principles, discusses the principles of modulation.

Module 13, Introduction to Number Systems and Logic Circuits, presents the fundamental concepts of
number systems, Boolean algebra, and logic circuits, all of which pertain to digital computers.

Module 14, Introduction to Microelectronics, covers microelectronics technology and miniature and
microminiature circuit repair.

Module 15, Principles of Synchros, Servos, and Gyros, provides the basic principles, operations,
functions, and applications of synchro, servo, and gyro mechanisms.

Module 16, Introduction to Test Equipment, is an introduction to some of the more commonly used test
equipments and their applications.

Module 17, Radio-Frequency Communications Principles, presents the fundamentals of a radio-
frequency communications system.

Module 18, Radar Principles, covers the fundamentals of a radar system.

Module 19, The Technician's Handbook, is a handy reference of commonly used general information,
such as electrical and electronic formulas, color coding, and naval supply system data.

Module 20, Master Glossary, is the glossary of terms for the series.

Module 21, Test Methods and Practices, describes basic test methods and practices.

Module 22, Introduction to Digital Computers, is an introduction to digital computers.

Module 23, Magnetic Recording, is an introduction to the use and maintenance of magnetic recorders and
the concepts of recording on magnetic tape and disks.

Module 24, Introduction to Fiber Optics, is an introduction to fiber optics.

Embedded questions are inserted throughout each module, except for modules 19 and 20, which are
reference books. If you have any difficulty in answering any of the questions, restudy the applicable
section.

Although an attempt has been made to use simple language, various technical words and phrases have
necessarily been included. Specific terms are defined in Module 20, Master Glossary.

Considerable emphasis has been placed on illustrations to provide a maximum amount of information. In
some instances, a knowledge of basic algebra may be required.

Assignments are provided for each module, with the exceptions of Module 19, The Technician's
Handbook; and Module 20, Master Glossary. Course descriptions and ordering information are in
NAVEDTRA 12061, Catalog of Nonresident Training Courses.

v

Throughout the text of this course and while using technical manuals associated with the equipment you
will be working on, you will find the below notations at the end of some paragraphs. The notations are
used to emphasize that safety hazards exist and care must be taken or observed.

WARNING

AN OPERATING PROCEDURE, PRACTICE, OR CONDITION, ETC., WHICH MAY
RESULT IN INJURY OR DEATH IF NOT CAREFULLY OBSERVED OR
FOLLOWED.

CAUTION

AN OPERATING PROCEDURE, PRACTICE, OR CONDITION, ETC., WHICH MAY
RESULT IN DAMAGE TO EQUIPMENT IF NOT CAREFULLY OBSERVED OR
FOLLOWED.

NOTE

An operating procedure, practice, or condition, etc., which is essential to emphasize.

vi

INSTRUCTIONS FOR TAKING THE COURSE

ASSIGNMENTS assignments. To submit your assignment
answers via the Internet, go to:
The text pages that you are to study are listed at
the beginning of each assignment. Study these http://courses.cnet.navy.mil
pages carefully before attempting to answer the
questions. Pay close attention to tables and Grading by Mail: When you submit answer
illustrations and read the learning objectives. sheets by mail, send all of your assignments at
The learning objectives state what you should be one time. Do NOT submit individual answer
able to do after studying the material. Answering sheets for grading. Mail all of your assignments
the questions correctly helps you accomplish the in an envelope, which you either provide
objectives. yourself or obtain from your nearest Educational
Services Officer (ESO). Submit answer sheets
SELECTING YOUR ANSWERS to:

Read each question carefully, then select the COMMANDING OFFICER
BEST answer. You may refer freely to the text. NETPDTC N331
The answers must be the result of your own 6490 SAUFLEY FIELD ROAD
work and decisions. You are prohibited from PENSACOLA FL 32559-5000
referring to or copying the answers of others and
from giving answers to anyone else taking the Answer Sheets: All courses include one
course. “scannable” answer sheet for each assignment.
These answer sheets are preprinted with your
SUBMITTING YOUR ASSIGNMENTS SSN, name, assignment number, and course
number. Explanations for completing the answer
To have your assignments graded, you must be sheets are on the answer sheet.
enrolled in the course with the Nonresident
Training Course Administration Branch at the Do not use answer sheet reproductions: Use
Naval Education and Training Professional only the original answer sheets that we
Development and Technology Center provide—reproductions will not work with our
(NETPDTC). Following enrollment, there are scanning equipment and cannot be processed.
two ways of having your assignments graded:
(1) use the Internet to submit your assignments Follow the instructions for marking your
as you complete them, or (2) send all the answers on the answer sheet. Be sure that blocks
assignments at one time by mail to NETPDTC. 1, 2, and 3 are filled in correctly. This
information is necessary for your course to be
Grading on the Internet: Advantages to properly processed and for you to receive credit
Internet grading are: for your work.

• you may submit your answers as soon as COMPLETION TIME
you complete an assignment, and
• you get your results faster; usually by the Courses must be completed within 12 months
next working day (approximately 24 hours). from the date of enrollment. This includes time
required to resubmit failed assignments.
In addition to receiving grade results for each
assignment, you will receive course completion
confirmation once you have completed all the

vii

PASS/FAIL ASSIGNMENT PROCEDURES For subject matter questions:

If your overall course score is 3.2 or higher, you E-mail: n315.products@cnet.navy.mil
will pass the course and will not be required to Phone: Comm: (850) 452-1001, ext. 1728
resubmit assignments. Once your assignments DSN: 922-1001, ext. 1728
have been graded you will receive course FAX: (850) 452-1370
completion confirmation. (Do not fax answer sheets.)
Address: COMMANDING OFFICER
If you receive less than a 3.2 on any assignment NETPDTC N315
and your overall course score is below 3.2, you 6490 SAUFLEY FIELD ROAD
will be given the opportunity to resubmit failed PENSACOLA FL 32509-5237
assignments. You may resubmit failed
assignments only once. Internet students will For enrollment, shipping, grading, or
receive notification when they have failed an completion letter questions
assignment--they may then resubmit failed
assignments on the web site. Internet students E-mail: fleetservices@cnet.navy.mil
may view and print results for failed Phone: Toll Free: 877-264-8583
assignments from the web site. Students who Comm: (850) 452-1511/1181/1859
submit by mail will receive a failing result letter DSN: 922-1511/1181/1859
and a new answer sheet for resubmission of each FAX: (850) 452-1370
failed assignment. (Do not fax answer sheets.)
Address: COMMANDING OFFICER
COMPLETION CONFIRMATION NETPDTC N331
6490 SAUFLEY FIELD ROAD
After successfully completing this course, you PENSACOLA FL 32559-5000
will receive a letter of completion.
NAVAL RESERVE RETIREMENT CREDIT
ERRATA
If you are a member of the Naval Reserve, you
Errata are used to correct minor errors or delete will receive retirement points if you are
obsolete information in a course. Errata may authorized to receive them under current
also be used to provide instructions to the directives governing retirement of Naval
student. If a course has an errata, it will be Reserve personnel. For Naval Reserve
included as the first page(s) after the front cover. retirement, this course is evaluated at 3 points.
Errata for all courses can be accessed and (Refer to Administrative Procedures for Naval
viewed/downloaded at: Reservists on Inactive Duty, BUPERSINST
1001.39, for more information about retirement
http://www.advancement.cnet.navy.mil points.)

STUDENT FEEDBACK QUESTIONS

We value your suggestions, questions, and
criticisms on our courses. If you would like to
communicate with us regarding this course, we
encourage you, if possible, to use e-mail. If you
write or fax, please use a copy of the Student
Comment form that follows this page.

viii

Student Comments
NEETS Module 4
Introduction to Electrical Conductors, Wiring Techniques, and Schematic
Course Title: Reading

NAVEDTRA: 14176 Date:

We need some information about you:

Rate/Rank and Name: SSN: Command/Unit

Street Address: City: State/FPO: Zip

Your comments, suggestions, etc.:

Privacy Act Statement: Under authority of Title 5, USC 301, information regarding your military status is
requested in processing your comments and in preparing a reply. This information will not be divulged without
written authorization to anyone other than those within DOD for official use in determining performance.

NETPDTC 1550/41 (Rev 4-00)

ix

CHAPTER 1
ELECTRICAL CONDUCTORS

LEARNING OBJECTIVES
/HDUQLQJ REMHFWLYHV DUH VWDWHG DW WKH EHJLQQLQJ RI HDFK FKDSWHU 7KHVH OHDUQLQJ REMHFWLYHV VHUYH DV D
SUHYLHZ RI WKH LQIRUPDWLRQ RX DUH H[SHFWHG WR OHDUQ LQ WKH FKDSWHU 7KH FRPSUHKHQVLYH FKHFN TXHVWLRQV
DUH EDVHG RQ WKH REMHFWLYHV % VXFFHVVIXOO FRPSOHWLQJ WKH 2( RX LQGLFDWH WKDW RX KDYH PHW
WKH REMHFWLYHV DQG KDYH OHDUQHG WKH LQIRUPDWLRQ 7KH OHDUQLQJ REMHFWLYHV DUH OLVWHG EHORZ
8SRQ FRPSOHWLQJ WKLV FKDSWHU RX VKRXOG EH DEOH WR
5HFDOO WKH GHILQLWLRQV RI XQLW VL]H PLOIRRW VTXDUH PLO DQG FLUFXODU PLO DQG WKH PDWKHPDWLFDO
HTXDWLRQV DQG FDOFXODWLRQV IRU HDFK
'HILQH VSHFLILF UHVLVWDQFH DQG UHFDOO WKH WKUHH IDFWRUV XVHG WR FDOFXODWH LW LQ RKPV
'HVFULEH WKH SURSHU XVH RI WKH $PHULFDQ :LUH *DXJH ZKHQ PDNLQJ ZLUH PHDVXUHPHQWV
5HFDOO WKH IDFWRUV UHTXLUHG LQ VHOHFWLQJ SURSHU VL]H ZLUH
6WDWH WKH DGYDQWDJHV DQG GLVDGYDQWDJHV RI FRSSHU RU DOXPLQXP DV FRQGXFWRUV
'HILQH LQVXODWLRQ UHVLVWDQFH DQG GLHOHFWULF VWUHQJWK LQFOXGLQJ KRZ WKH GLHOHFWULF VWUHQJWK RI DQ
LQVXODWRU LV GHWHUPLQHG
,GHQWLI WKH VDIHW SUHFDXWLRQV WR EH WDNHQ ZKHQ ZRUNLQJ ZLWK LQVXODWLQJ PDWHULDOV
5HFDOO WKH PRVW FRPPRQ LQVXODWRUV XVHG IRU H[WUHPHO KLJK YROWDJHV
6WDWH WKH WSH RI FRQGXFWRU SURWHFWLRQ QRUPDOO XVHG IRU VKLSERDUG ZLULQJ
5HFDOO WKH GHVLJQ DQG XVH RI FRD[LDO FDEOH

ELECTRICAL CONDUCTORS
,Q WKH SUHYLRXV PRGXOHV RI WKLV WUDLQLQJ VHULHV RX KDYH OHDUQHG DERXW YDULRXV FLUFXLW FRPSRQHQWV
7KHVH FRPSRQHQWV SURYLGH WKH PDMRULW RI WKH RSHUDWLQJ FKDUDFWHULVWLFV RI DQ HOHFWULFDO FLUFXLW 7KH DUH
XVHOHVV KRZHYHU LI WKH DUH QRW FRQQHFWHG WRJHWKHU RQGXFWRUV DUH WKH PHDQV XVHG WR WLH WKHVH
FRPSRQHQWV WRJHWKHU
0DQ IDFWRUV GHWHUPLQH WKH WSH RI HOHFWULFDO FRQGXFWRU XVHG WR FRQQHFW FRPSRQHQWV 6RPH RI WKHVH
IDFWRUV DUH WKH SKVLFDO VL]H RI WKH FRQGXFWRU LWV FRPSRVLWLRQ DQG LWV HOHFWULFDO FKDUDFWHULVWLFV 2WKHU
IDFWRUV WKDW FDQ GHWHUPLQH WKH FKRLFH RI D FRQGXFWRU DUH WKH ZHLJKW WKH FRVW DQG WKH HQYLURQPHQW ZKHUH
WKH FRQGXFWRU ZLOO EH XVHG

CONDUCTOR SIZES
7R FRPSDUH WKH UHVLVWDQFH DQG VL]H RI RQH FRQGXFWRU ZLWK WKDW RI DQRWKHU ZH QHHG WR HVWDEOLVK D
VWDQGDUG RU XQLW VL]H $ FRQYHQLHQW XQLW RI PHDVXUHPHQW RI WKH GLDPHWHU RI D FRQGXFWRU LV WKH PLO
RU RQHWKRXVDQGWK RI DQ LQFK

$ FRQYHQLHQW XQLW RI FRQGXFWRU OHQJWK LV WKH IRRW 7KH VWDQGDUG XQLW RI VL]H
LQ PRVW FDVHV LV WKH 0,/)227 $ ZLUH ZLOO KDYH D XQLW VL]H LI LW KDV D GLDPHWHU RI PLO DQG D OHQJWK RI
IRRW

SQUARE MIL
7KH VTXDUH PLO LV D XQLW RI PHDVXUHPHQW XVHG WR GHWHUPLQH WKH FURVVVHFWLRQDO DUHD RI D VTXDUH RU
UHFWDQJXODU FRQGXFWRU YLHZV $ DQG % RI ILJXUH

$ VTXDUH PLO LV GHILQHG DV WKH DUHD RI D VTXDUH WKH
VLGHV RI ZKLFK DUH HDFK PLO 7R REWDLQ WKH FURVVVHFWLRQDO DUHD RI D VTXDUH FRQGXFWRU PXOWLSO WKH
GLPHQVLRQ RI DQ VLGH RI WKH VTXDUH E LWVHOI )RU H[DPSOH DVVXPH WKDW RX KDYH D VTXDUH FRQGXFWRU ZLWK
D VLGH GLPHQVLRQ RI PLOV 0XOWLSO PLOV E LWVHOI PLOV × PLOV

7KLV JLYHV RX D FURVVVHFWLRQDO
DUHD RI VTXDUH PLOV

Figure 1-1.—Cross-sectional areas of conductors.
Q1. State the reason for the establishment of a unit size for conductors.
Q2. Calculate the diameter in MILS of a conductor that has a diameter of 0.375 inch.
Q3. Define a mil-foot.
7R GHWHUPLQH WKH FURVVVHFWLRQDO DUHD RI D UHFWDQJXODU FRQGXFWRU PXOWLSO WKH OHQJWK WLPHV WKH ZLGWK
RI WKH HQG IDFH RI WKH FRQGXFWRU VLGH LV H[SUHVVHG LQ PLOV

)RU H[DPSOH DVVXPH WKDW RQH VLGH RI WKH
UHFWDQJXODU FURVVVHFWLRQDO DUHD LV PLOV DQG WKH RWKHU VLGH LV PLOV 0XOWLSO PLOV × PLOV ZKLFK
HTXDOV VTXDUH PLOV +HUH LV DQRWKHU H[DPSOH $VVXPH WKDW D FRQGXFWRU LV LQFK WKLFN DQG LQFKHV
ZLGH 7KH LQFK FDQ EH H[SUHVVHG LQ GHFLPDO IRUP DV LQFK 6LQFH PLO HTXDOV LQFK WKH
WKLFNQHVV RI WKH FRQGXFWRU ZLOO EH × RU PLOV 6LQFH WKH ZLGWK LV LQFKHV DQG WKHUH DUH
PLOV SHU LQFK WKH ZLGWK ZLOO EH × RU PLOV 7R GHWHUPLQH WKH FURVVVHFWLRQDO DUHD
PXOWLSO WKH OHQJWK E WKH ZLGWK RU PLOV × PLOV 7KH DUHD ZLOO EH VTXDUH PLOV
Q4. Define a square mil as it relates to a square conductor.
CIRCULAR MIL
7KH FLUFXODU PLO LV WKH VWDQGDUG XQLW RI PHDVXUHPHQW RI D URXQG ZLUH FURVVVHFWLRQDO DUHD YLHZ RI
ILJXUH

7KLV XQLW RI PHDVXUHPHQW LV IRXQG LQ $PHULFDQ DQG (QJOLVK ZLUH WDEOHV 7KH GLDPHWHU RI D
URXQG FRQGXFWRU ZLUH

XVHG WR FRQGXFW HOHFWULFLW PD EH RQO D IUDFWLRQ RI DQ LQFK 7KHUHIRUH LW LV
FRQYHQLHQW WR H[SUHVV WKLV GLDPHWHU LQ PLOV WR DYRLG XVLQJ GHFLPDOV )RU H[DPSOH WKH GLDPHWHU RI D ZLUH LV
H[SUHVVHG DV PLOV LQVWHDG RI LQFK $ FLUFXODU PLO LV WKH DUHD RI D FLUFOH KDYLQJ D GLDPHWHU RI
PLO DV VKRZQ LQ YLHZ % RI ILJXUH 7KH DUHD LQ FLUFXODU PLOV RI D URXQG FRQGXFWRU LV REWDLQHG E
VTXDULQJ WKH GLDPHWHU PHDVXUHG LQ PLOV 7KXV D ZLUH KDYLQJ D GLDPHWHU RI PLOV KDV DQ DUHD RI RU
FLUFXODU PLOV 7R GHWHUPLQH WKH QXPEHU RI VTXDUH PLOV LQ WKH VDPH FRQGXFWRU DSSO WKH FRQYHQWLRQDO
IRUPXOD IRU GHWHUPLQLQJ WKH DUHD RI D FLUFOH $ πU

LV WKH XQNQRZQ DQG LV
HTXDO WR WKH FURVVVHFWLRQDO DUHD LQ VTXDUH PLOV π LV WKH FRQVWDQW DQG U LV WKH UDGLXV RI WKH FLUFOH RU
KDOI WKH GLDPHWHU '

VTXDUH PLOV 7KH FURVVVHFWLRQDO DUHD RI WKH ZLUH KDV FLUFXODU PLOV EXW RQO VTXDUH PLOV
7KHUHIRUH D FLUFXODU PLO UHSUHVHQWV D VPDOOHU XQLW RI DUHD WKDQ WKH VTXDUH PLO

Figure 1-2.—A comparison of circular and square mils.
,I D ZLUH KDV D FURVVVHFWLRQDO GLDPHWHU RI PLO E GHILQLWLRQ WKH FLUFXODU PLO DUHD 0$

LV $
' RU $ RU $ FLUFXODU PLO 7R GHWHUPLQH WKH VTXDUH PLO DUHD RI WKH VDPH ZLUH DSSO WKH IRUPXOD
$ πU WKHUHIRUH $ ×

UHSUHVHQWLQJ KDOI WKH GLDPHWHU

:KHQ $ × $
VTXDUH PLO )URP WKLV LW FDQ EH FRQFOXGHG WKDW FLUFXODU PLO LV HTXDO WR VTXDUH PLO 7KLV EHFRPHV
LPSRUWDQW ZKHQ VTXDUH YLHZ $ RI ILJXUH

FRQGXFWRUV DUH FRPSDUHG DV LQ YLHZ
RI ILJXUH
:KHQ WKH VTXDUH PLO DUHD LV JLYHQ GLYLGH WKH DUHD E WR GHWHUPLQH WKH FLUFXODU PLO DUHD RU
0$ :KHQ WKH 0$ LV JLYHQ PXOWLSO WKH DUHD E WR GHWHUPLQH WKH VTXDUH PLO DUHD )RU
H[DPSOH
3UREOHP $ JDXJH ZLUH KDV D GLDPHWHU RI PLOV :KDW LV

LWV DUHD LQ VTXDUH PLOV

3UREOHP $ UHFWDQJXODU FRQGXFWRU LV LQFKHV ZLGH DQG LQFK WKLFN :KDW LV

LQ FLUFXODU PLOV :KDW VL]H RI URXQG FRQGXFWRU LV QHFHVVDU WR FDUU WKH VDPH FXUUHQW
DV WKH UHFWDQJXODU EDU

$ ZLUH LQ LWV XVXDO IRUP LV D VLQJOH VOHQGHU URG RU ILODPHQW RI GUDZQ PHWDO ,Q ODUJH VL]HV ZLUH
EHFRPHV GLIILFXOW WR KDQGOH 7R LQFUHDVH LWV IOH[LELOLW LW LV VWUDQGHG 6WUDQGV DUH XVXDOO VLQJOH ZLUHV
WZLVWHG WRJHWKHU LQ VXIILFLHQW QXPEHUV WR PDNH XS WKH QHFHVVDU FURVVVHFWLRQDO DUHD RI WKH FDEOH 7KH
WRWDO DUHD RI VWUDQGHG ZLUH LQ FLUFXODU PLOV LV GHWHUPLQHG E PXOWLSOLQJ WKH DUHD LQ FLUFXODU PLOV RI RQH
VWUDQG E WKH QXPEHU RI VWUDQGV LQ WKH FDEOH
Q5. Define a circular mil.
Q6. What is the circular mil area of a 19-strand conductor if each strand is 0.004 inch?
CIRCULAR-MIL-FOOT
$ FLUFXODUPLOIRRW ILJXUH

LV D XQLW RI YROXPH ,W LV D XQLW FRQGXFWRU IRRW LQ OHQJWK DQG KDV D
FURVVVHFWLRQDO DUHD RI FLUFXODU PLO %HFDXVH LW LV D XQLW FRQGXFWRU WKH FLUFXODUPLOIRRW LV XVHIXO LQ
PDNLQJ FRPSDULVRQV EHWZHHQ ZLUHV FRQVLVWLQJ RI GLIIHUHQW PHWDOV )RU H[DPSOH D EDVLV RI FRPSDULVRQ RI
WKH 5(6,67,9,7 WR EH GLVFXVVHG VKRUWO

RI YDULRXV VXEVWDQFHV PD EH PDGH E GHWHUPLQLQJ WKH
UHVLVWDQFH RI D FLUFXODUPLOIRRW RI HDFK RI WKH VXEVWDQFHV

Figure 1-3.—Circular-mil-foot.
,Q ZRUNLQJ ZLWK VTXDUH RU UHFWDQJXODU FRQGXFWRUV VXFK DV DPPHWHU VKXQWV DQG EXV EDUV RX PD
VRPHWLPHV ILQG LW PRUH FRQYHQLHQW WR XVH D GLIIHUHQW XQLW YROXPH $ EXV EDU LV D KHDY FRSSHU VWUDS RU EDU
XVHG WR FRQQHFW VHYHUDO FLUFXLWV WRJHWKHU %XV EDUV DUH XVHG ZKHQ D ODUJH FXUUHQW FDSDFLW LV UHTXLUHG 8QLW
YROXPH PD EH PHDVXUHG DV WKH FHQWLPHWHU FXEH 6SHFLILF UHVLVWDQFH WKHUHIRUH EHFRPHV WKH UHVLVWDQFH

RIIHUHG E D FXEHVKDSHG FRQGXFWRU FHQWLPHWHU LQ OHQJWK DQG VTXDUH FHQWLPHWHU LQ FURVVVHFWLRQDO DUHD
7KH XQLW RI YROXPH WR EH XVHG LV JLYHQ LQ WDEOHV RI VSHFLILF UHVLVWDQFHV

SPECIFIC RESISTANCE OR RESISTIVITY
6SHFLILF UHVLVWDQFH RU UHVLVWLYLW LV WKH UHVLVWDQFH LQ RKPV RIIHUHG E D XQLW YROXPH WKH FLUFXODUPLO
IRRW RU WKH FHQWLPHWHU FXEH

RI D VXEVWDQFH WR WKH IORZ RI HOHFWULF FXUUHQW 5HVLVWLYLW LV WKH UHFLSURFDO RI
FRQGXFWLYLW $ VXEVWDQFH WKDW KDV D KLJK UHVLVWLYLW ZLOO KDYH D ORZ FRQGXFWLYLW DQG YLFH YHUVD 7KXV
WKH VSHFLILF UHVLVWDQFH RI D VXEVWDQFH LV WKH UHVLVWDQFH RI D XQLW YROXPH RI WKDW VXEVWDQFH
0DQ WDEOHV RI VSHFLILF UHVLVWDQFH DUH EDVHG RQ WKH UHVLVWDQFH LQ RKPV RI D YROXPH RI D VXEVWDQFH
IRRW LQ OHQJWK DQG FLUFXODU PLO LQ FURVVVHFWLRQDO DUHD 7KH WHPSHUDWXUH DW ZKLFK WKH UHVLVWDQFH
PHDVXUHPHQW LV PDGH LV DOVR VSHFLILHG ,I RX NQRZ WKH NLQG RI PHWDO D FRQGXFWRU LV PDGH RI RX FDQ
REWDLQ WKH VSHFLILF UHVLVWDQFH RI WKH PHWDO IURP D WDEOH 7KH VSHFLILF UHVLVWDQFHV RI VRPH FRPPRQ
VXEVWDQFHV DUH JLYHQ LQ WDEOH

Table 1-1.—Specific Resistances of Common Substances
6XEVWDQFH 6SHFLILF UHVLVWDQFH DW ž
HQWLPHWHU FXEH LUFXODUPLOIRRW
PLFURKRPV

*ROG
$OXPLQXP
DUERQ DPRUSKRXV

WR ««««««««
7XQJVWHQ
%UDVV
6WHHO VRIW

1LFKURPH

7KH UHVLVWDQFH RI D FRQGXFWRU RI D XQLIRUP FURVV VHFWLRQ YDULHV GLUHFWO DV WKH SURGXFW RI WKH OHQJWK
DQG WKH VSHFLILF UHVLVWDQFH RI WKH FRQGXFWRU DQG LQYHUVHO DV WKH FURVVVHFWLRQDO DUHD RI WKH FRQGXFWRU
7KHUHIRUH RX FDQ FDOFXODWH WKH UHVLVWDQFH RI D FRQGXFWRU LI RX NQRZ WKH OHQJWK FURVVVHFWLRQDO DUHD
DQG VSHFLILF UHVLVWDQFH RI WKH VXEVWDQFH ([SUHVVHG DV DQ HTXDWLRQ WKH 5 UHVLVWDQFH LQ RKPV

3UREOHP
:KDW LV WKH UHVLVWDQFH RI IHHW RI FRSSHU ZLUH KDYLQJ D FURVVVHFWLRQDO DUHD RI FLUFXODU
PLOV 1R ZLUH

DW D WHPSHUDWXUH RI ž
6ROXWLRQ
7KH VSHFLILF UHVLVWDQFH RI FRSSHU WDEOH

LV RKPV 6XEVWLWXWLQJ WKH NQRZQ YDOXHV LQ WKH
SUHFHGLQJ HTXDWLRQ WKH UHVLVWDQFH 5 LV GHWHUPLQHG DV

,I 5 DQG $ DUH NQRZQ WKH OHQJWK /

FDQ EH GHWHUPLQHG E D VLPSOH PDWKHPDWLFDO WUDQVSRVLWLRQ
7KLV KDV PDQ YDOXDEOH DSSOLFDWLRQV )RU H[DPSOH ZKHQ ORFDWLQJ D JURXQG LQ D WHOHSKRQH OLQH RX ZLOO
XVH VSHFLDO WHVW HTXLSPHQW 7KLV HTXLSPHQW RSHUDWHV RQ WKH SULQFLSOH WKDW WKH UHVLVWDQFH RI D OLQH YDULHV
GLUHFWO ZLWK LWV OHQJWK 7KXV WKH GLVWDQFH EHWZHHQ WKH WHVW SRLQW DQG D IDXOW FDQ EH FRPSXWHG DFFXUDWHO
Q7. Define specific resistance.
Q8. List the three factors used to calculate resistance of a particular conductor in ohms.
WIRE SIZES
7KH PRVW FRPPRQ PHWKRG IRU PHDVXULQJ ZLUH VL]H LQ WKH 1DY LV E XVLQJ WKH $PHULFDQ :LUH
*DXJH $:*

$Q H[FHSWLRQ LV DLUFUDIW ZLULQJ ZKLFK YDULHV VOLJKWO LQ VL]H DQG IOH[LELOLW IURP $:*
VWDQGDUGV )RU LQIRUPDWLRQ FRQFHUQLQJ DLUFUDIW ZLUH VL]HV UHIHU WR WKH SURSHU SXEOLFDWLRQV IRU VSHFLILF
DLUFUDIW 2QO $:* ZLUH VL]HV DUH XVHG LQ WKH IROORZLQJ GLVFXVVLRQ

:LUH LV PDQXIDFWXUHG LQ VL]HV QXPEHUHG DFFRUGLQJ WR WKH $:* WDEOHV 7KH YDULRXV ZLUHV VROLG RU
VWUDQGHG

DQG WKH PDWHULDO WKH DUH PDGH IURP FRSSHU DOXPLQXP DQG VR IRUWK

DUH SXEOLVKHG E WKH
1DWLRQDO %XUHDX RI 6WDQGDUGV $Q $:* WDEOH IRU FRSSHU ZLUH LV VKRZQ DW WDEOH 7KH ZLUH GLDPHWHUV
EHFRPH VPDOOHU DV WKH JDXJH QXPEHUV EHFRPH ODUJHU 1XPEHUV DUH URXQGHG RII IRU FRQYHQLHQFH EXW DUH
DFFXUDWH IRU SUDFWLFDO DSSOLFDWLRQ 7KH ODUJHVW ZLUH VL]H VKRZQ LQ WKH WDEOH LV UHDG QDXJKW

DQG
WKH VPDOOHVW LV QXPEHU /DUJHU DQG VPDOOHU VL]HV DUH PDQXIDFWXUHG EXW DUH QRW FRPPRQO XVHG E WKH
1DY $:* WDEOHV VKRZ WKH GLDPHWHU LQ PLOV FLUFXODU PLO DUHD DQG DUHD LQ VTXDUH LQFKHV RI $:* ZLUH
VL]HV 7KH DOVR VKRZ WKH UHVLVWDQFH RKPV

SHU WKRXVDQG IHHW DQG SHU PLOH RI ZLUH VL]HV DW VSHFLILF
WHPSHUDWXUHV 7KH ODVW FROXPQ VKRZV WKH ZHLJKW RI WKH ZLUH SHU WKRXVDQG IHHW $Q H[DPSOH RI WKH XVH RI
WDEOH LV DV IROORZV

Table 1-2.—Standard Solid Copper (American Wire Gauge)

*DJH 'LDPHWHU URVV 6HFWLRQ 2KPV SHU IW 2KPV SHU 3RXQGV SHU
QXPEHU PLOV

PLOH ž IW
LUFXODU PLOV 6TXDUH LQFKHV ž ž ž)
ž) ž)

3UREOHP RX DUH UHTXLUHG WR UXQ IHHW RI $:* VROLG FRSSHU ZLUH IRU D QHZ SLHFH RI
HTXLSPHQW 7KH WHPSHUDWXUH ZKHUH WKH ZLUH LV WR EH UXQ LV ž ž )

+RZ PXFK
UHVLVWDQFH ZLOO WKH ZLUH RIIHU WR FXUUHQW IORZ

6ROXWLRQ 8QGHU WKH JDXJH QXPEHU FROXPQ ILQG VL]H $:* 1RZ UHDG DFURVV WKH FROXPQV XQWLO
RX UHDFK WKH RKPV SHU IHHW IRU ž ž )

FROXPQ RX ZLOO ILQG WKDW WKH ZLUH
ZLOO RIIHU RKPV RI UHVLVWDQFH WR FXUUHQW IORZ 6LQFH ZH DUH XVLQJ IHHW RI ZLUH
PXOWLSO E
RKPV × RKPV
$Q $PHULFDQ 6WDQGDUG :LUH *DXJH ILJXUH

LV XVHG WR PHDVXUH ZLUHV UDQJLQJ LQ VL]H IURP
QXPEHU WR QXPEHU 7R XVH WKLV JDXJH LQVHUW WKH ZLUH WR EH PHDVXUHG LQWR WKH VPDOOHVW VORW WKDW ZLOO
MXVW DFFRPPRGDWH WKH EDUH ZLUH 7KH JDXJH QXPEHU RQ WKDW VORW LQGLFDWHV WKH ZLUH VL]H 7KH IURQW SDUW RI
WKH VORW KDV SDUDOOHO VLGHV DQG WKLV LV ZKHUH WKH ZLUH PHDVXUHPHQW LV WDNHQ ,W VKRXOG QRW EH FRQIXVHG ZLWK
WKH ODUJHU VHPLFLUFXODU RSHQLQJ DW WKH UHDU RI WKH VORW 7KH UHDU RSHQLQJ VLPSO SHUPLWV WKH IUHH PRYHPHQW
RI WKH ZLUH DOO WKH ZD WKURXJK WKH VORW

Figure 1-4.—Wire gauge.

Q9. Using table 1-2, determine the resistance of 1,500 feet of AWG 20 wire at 25º C.
Q10. When using an American Standard Wire Gauge to determine the size of a wire, where should
you place the wire in the gauge to get the correct measurement?
STRANDED WIRES AND CABLES
$ ZLUH LV D VLQJOH VOHQGHU URG RU ILODPHQW RI GUDZQ PHWDO 7KLV GHILQLWLRQ UHVWULFWV WKH WHUP WR ZKDW
ZRXOG RUGLQDULO EH XQGHUVWRRG DV VROLG ZLUH 7KH ZRUG VOHQGHU LV XVHG EHFDXVH WKH OHQJWK RI D ZLUH LV
XVXDOO ODUJH ZKHQ FRPSDUHG WR LWV GLDPHWHU ,I D ZLUH LV FRYHUHG ZLWK LQVXODWLRQ LW LV DQ LQVXODWHG ZLUH
$OWKRXJK WKH WHUP ZLUH SURSHUO UHIHUV WR WKH PHWDO LW DOVR LQFOXGHV WKH LQVXODWLRQ
$ FRQGXFWRU LV D ZLUH VXLWDEOH IRU FDUULQJ DQ HOHFWULF FXUUHQW
$ VWUDQGHG FRQGXFWRU LV D FRQGXFWRU FRPSRVHG RI D JURXS RI ZLUHV RU RI DQ FRPELQDWLRQ RI JURXSV
RI ZLUHV 7KH ZLUHV LQ D VWUDQGHG FRQGXFWRU DUH XVXDOO WZLVWHG WRJHWKHU DQG QRW LQVXODWHG IURP HDFK RWKHU
$ FDEOH LV HLWKHU D VWUDQGHG FRQGXFWRU VLQJOHFRQGXFWRU FDEOH

RU D FRPELQDWLRQ RI FRQGXFWRUV
LQVXODWHG IURP RQH DQRWKHU PXOWLSOHFRQGXFWRU FDEOH

7KH WHUP FDEOH LV D JHQHUDO RQH DQG XVXDOO
DSSOLHV RQO WR WKH ODUJHU VL]HV RI FRQGXFWRUV $ VPDOO FDEOH LV PRUH RIWHQ FDOOHG D VWUDQGHG ZLUH RU FRUG
VXFK DV WKDW XVHG IRU DQ LURQ RU D ODPS FRUG

DEOHV PD EH EDUH RU LQVXODWHG ,QVXODWHG FDEOHV PD EH
VKHDWKHG FRYHUHG

ZLWK OHDG RU SURWHFWLYH DUPRU )LJXUH VKRZV GLIIHUHQW WSHV RI ZLUH DQG FDEOH XVHG
LQ WKH 1DY

Figure 1-5.—Conductors.
RQGXFWRUV DUH VWUDQGHG PDLQO WR LQFUHDVH WKHLU IOH[LELOLW 7KH ZLUH VWUDQGV LQ FDEOHV DUH DUUDQJHG
LQ WKH IROORZLQJ RUGHU
7KH ILUVW ODHU RI VWUDQGV DURXQG WKH FHQWHU FRQGXFWRU LV PDGH XS RI VL[ FRQGXFWRUV 7KH VHFRQG ODHU
LV PDGH XS RI DGGLWLRQDO FRQGXFWRUV 7KH WKLUG ODHU LV PDGH XS RI DGGLWLRQDO FRQGXFWRUV DQG VR RQ
7KXV VWDQGDUG FDEOHV DUH FRPSRVHG RI DQG VWUDQGV LQ FRQWLQXLQJ IL[HG LQFUHPHQWV 7KH RYHUDOO
IOH[LELOLW FDQ EH LQFUHDVHG E IXUWKHU VWUDQGLQJ RI WKH LQGLYLGXDO VWUDQGV
)LJXUH VKRZV D WSLFDO FURVV VHFWLRQ RI D VWUDQG FDEOH ,W DOVR VKRZV KRZ WKH WRWDO FLUFXODUPLO
FURVVVHFWLRQDO DUHD RI D VWUDQGHG FDEOH LV GHWHUPLQHG

Figure 1-6.—Stranded conductor.

SELECTION OF WIRE SIZE
6HYHUDO IDFWRUV PXVW EH FRQVLGHUHG LQ VHOHFWLQJ WKH VL]H RI ZLUH WR EH XVHG IRU WUDQVPLWWLQJ DQG
GLVWULEXWLQJ HOHFWULF SRZHU 7KHVH IDFWRUV ZLOO EH GLVFXVVHG WKURXJKRXW WKLV VHFWLRQ 0LOLWDU VSHFLILFDWLRQV
FRYHU WKH LQVWDOODWLRQ RI ZLULQJ LQ DLUFUDIW VKLSV DQG HOHFWULFDOHOHFWURQLF HTXLSPHQW 7KHVH VSHFLILFDWLRQV
GHVFULEH WKH WHFKQLFDO UHTXLUHPHQWV IRU PDWHULDO SXUFKDVHG IURP PDQXIDFWXUHUV E WKH 'HSDUWPHQW RI
'HIHQVH $Q LPSRUWDQW UHDVRQ IRU KDYLQJ WKHVH VSHFLILFDWLRQV LV WR HQVXUH XQLIRUPLW RI VL]HV WR UHGXFH WKH
GDQJHU RI ILUHV FDXVHG E WKH LPSURSHU VHOHFWLRQ RI ZLUH VL]HV :LUHV FDQ FDUU RQO D OLPLWHG DPRXQW RI
FXUUHQW VDIHO ,I WKH FXUUHQW IORZLQJ WKURXJK D ZLUH H[FHHGV WKH FXUUHQWFDUULQJ FDSDFLW RI WKH ZLUH
H[FHVV KHDW LV JHQHUDWHG 7KLV KHDW PD EH JUHDW HQRXJK WR EXUQ RII WKH LQVXODWLRQ DURXQG WKH ZLUH DQG
VWDUW D ILUH

FACTORS GOVERNING THE CURRENT RATING
7KH FXUUHQW UDWLQJ RI D FDEOH RU ZLUH LQGLFDWHV WKH FXUUHQW FDSDFLW WKDW WKH ZLUH RU FDEOH FDQ VDIHO
FDUU FRQWLQXRXVO ,I WKLV OLPLW RU FXUUHQW UDWLQJ LV H[FHHGHG IRU D OHQJWK RI WLPH WKH KHDW JHQHUDWHG PD
EXUQ WKH LQVXODWLRQ 7KH FXUUHQW UDWLQJ RI D ZLUH LV XVHG WR GHWHUPLQH ZKDW VL]H LV QHHGHG IRU D JLYHQ ORDG
RU FXUUHQW GUDLQ
7KH IDFWRUV WKDW GHWHUPLQH WKH FXUUHQW UDWLQJ RI D ZLUH DUH WKH FRQGXFWRU VL]H WKH ORFDWLRQ RI WKH ZLUH
LQ D FLUFXLW WKH WSH RI LQVXODWLRQ DQG WKH VDIH FXUUHQW UDWLQJ $QRWKHU IDFWRU WKDW ZLOO EH GLVFXVVHG ODWHU LQ
WKLV FKDSWHU LV WKH PDWHULDO WKH ZLUH LV PDGH RI $V RX KDYH DOUHDG VHHQ WKHVH IDFWRUV DOVR DIIHFW WKH
UHVLVWDQFH LQ RKPV RI D ZLUHFDUULQJ FXUUHQW
CONDUCTOR SIZE
$Q LQFUHDVH LQ WKH GLDPHWHU RU FURVV VHFWLRQ RI D ZLUH FRQGXFWRU GHFUHDVHV LWV UHVLVWDQFH DQG
LQFUHDVHV LWV FDSDFLW WR FDUU FXUUHQW $Q LQFUHDVH LQ WKH VSHFLILF UHVLVWDQFH RI D FRQGXFWRU LQFUHDVHV LWV
UHVLVWDQFH DQG GHFUHDVHV LWV FDSDFLW WR FDUU FXUUHQW
WIRE LOCATION
7KH ORFDWLRQ RI D ZLUH LQ D FLUFXLW GHWHUPLQHV WKH WHPSHUDWXUH XQGHU ZKLFK LW RSHUDWHV $ ZLUH PD EH
ORFDWHG LQ D FRQGXLW RU ODFHG ZLWK RWKHU ZLUHV LQ D FDEOH %HFDXVH LW LV FRQILQHG WKH ZLUH RSHUDWHV DW D
KLJKHU WHPSHUDWXUH WKDQ LI LW ZHUH RSHQ WR WKH IUHH DLU 7KH KLJKHU WKH WHPSHUDWXUH XQGHU ZKLFK D ZLUH LV
RSHUDWLQJ WKH JUHDWHU ZLOO EH LWV UHVLVWDQFH ,WV FDSDFLW WR FDUU FXUUHQW LV DOVR ORZHUHG 1RWH WKDW LQ HDFK
FDVH WKH UHVLVWDQFH RI D ZLUH GHWHUPLQHV LWV FXUUHQWFDUULQJ FDSDFLW 7KH JUHDWHU WKH UHVLVWDQFH WKH PRUH
SRZHU LW GLVVLSDWHV LQ WKH IRUP RI KHDW HQHUJ
RQGXFWRUV PD DOVR EH LQVWDOOHG LQ ORFDWLRQV ZKHUH WKH DPELHQW VXUURXQGLQJ

WHPSHUDWXUH LV
UHODWLYHO KLJK :KHQ WKLV LV WKH FDVH WKH KHDW JHQHUDWHG E H[WHUQDO VRXUFHV LV DQ LPSRUWDQW SDUW RI WKH
WRWDO FRQGXFWRU KHDWLQJ 7KLV KHDWLQJ IDFWRU ZLOO EH H[SODLQHG IXUWKHU ZKHQ ZH GLVFXVV WHPSHUDWXUH
FRHIILFLHQW :H PXVW XQGHUVWDQG KRZ H[WHUQDO KHDWLQJ LQIOXHQFHV KRZ PXFK FXUUHQW D FRQGXFWRU FDQ
FDUU (DFK FDVH KDV LWV RZQ VSHFLILF OLPLWDWLRQV 7KH PD[LPXP DOORZDEOH RSHUDWLQJ WHPSHUDWXUH RI
LQVXODWHG FRQGXFWRUV LV VSHFLILHG LQ WDEOHV ,W YDULHV ZLWK WKH WSH RI FRQGXFWRU LQVXODWLRQ EHLQJ XVHG
INSULATION
7KH LQVXODWLRQ RI D ZLUH GRHV QRW DIIHFW WKH UHVLVWDQFH RI WKH ZLUH 5HVLVWDQFH GRHV KRZHYHU
GHWHUPLQH KRZ PXFK KHDW LV QHHGHG WR EXUQ WKH LQVXODWLRQ $V FXUUHQW IORZV WKURXJK DQ LQVXODWHG
FRQGXFWRU WKH OLPLW RI FXUUHQW WKDW WKH FRQGXFWRU FDQ ZLWKVWDQG GHSHQGV RQ KRZ KRW WKH FRQGXFWRU FDQ JHW
EHIRUH LW EXUQV WKH LQVXODWLRQ 'LIIHUHQW WSHV RI LQVXODWLRQ ZLOO EXUQ DW GLIIHUHQW WHPSHUDWXUHV 7KHUHIRUH
WKH WSH RI LQVXODWLRQ XVHG LV WKH WKLUG IDFWRU WKDW GHWHUPLQHV WKH FXUUHQW UDWLQJ RI D FRQGXFWRU )RU

LQVWDQFH UXEEHU LQVXODWLRQ ZLOO EHJLQ GHWHULRUDWLQJ DW UHODWLYHO ORZ WHPSHUDWXUHV ZKHUHDV YDUQLVKHG FORWK
LQVXODWLRQ UHWDLQV LWV LQVXODWLQJ SURSHUWLHV DW KLJKHU WHPSHUDWXUHV 2WKHU WSHV RI LQVXODWLRQ DUH IOXRULQDWHG
HWKOHQH SURSOHQH )(3

VLOLFRQH UXEEHU RU H[WUXGHG SROWHWUDIOXRURHWKOHQH 7KH DUH HIIHFWLYH DW VWLOO
KLJKHU WHPSHUDWXUHV
SAFE CURRENT RATINGS
7KH 1DWLRQDO %RDUG RI )LUH 8QGHUZULWHUV SUHSDUHV WDEOHV VKRZLQJ WKH VDIH FXUUHQW UDWLQJV IRU VL]HV
DQG WSHV RI FRQGXFWRUV FRYHUHG ZLWK YDULRXV WSHV RI LQVXODWLRQ 7KH DOORZDEOH FXUUHQWFDUULQJ
FDSDFLWLHV RI VLQJOH FRSSHU FRQGXFWRUV LQ IUHH DLU DW D PD[LPXP URRP WHPSHUDWXUH RI ž ž )

DUH
JLYHQ LQ WDEOH $W DPELHQW WHPSHUDWXUHV JUHDWHU WKDQ ž WKHVH FRQGXFWRUV ZRXOG KDYH OHVV FXUUHQW
FDUULQJ FDSDFLW

Table 1-3.—Temperature Ratings and Current-Carrying Capacities (in Amperes) of Some Single Copper Conductors at
Ambient Temperatures of 30ºC

6L]H 0RLVWXUH 5HVLVWDQW 9DUQLVKHG DPEULF 6LOLFRQH 5XEEHU RU 3ROWHWUD
5XEEHU RU RU +HDW 5HVLVWDQW )OXRULQDWHG )OXRURHWKOHQH
7KHUPRSODVWLF 7KHUPRSODVWLF (WKOHQH 3URSOHQH
)(3

Q11. List the four factors you should use to select wire for a specified current rating.
Q12. What are three types of nonmetallic insulating materials that can be used in a high-temperature
environments?
Q13. State why it is important for you to consider the ambient (surrounding) temperature of a
conductor when selecting wire size.

COPPER-VERSUS-ALUMINUM CONDUCTORS
$OWKRXJK VLOYHU LV WKH EHVW FRQGXFWRU LWV FRVW OLPLWV LWV XVH WR VSHFLDO FLUFXLWV 6LOYHU LV XVHG ZKHUH D
VXEVWDQFH ZLWK KLJK FRQGXFWLYLW RU ORZ UHVLVWLYLW LV QHHGHG
7KH WZR PRVW FRPPRQO XVHG FRQGXFWRUV DUH FRSSHU DQG DOXPLQXP (DFK KDV SRVLWLYH DQG QHJDWLYH
FKDUDFWHULVWLFV WKDW DIIHFW LWV XVH XQGHU YDULQJ FLUFXPVWDQFHV $ FRPSDULVRQ RI VRPH RI WKH
FKDUDFWHULVWLFV RI FRSSHU DQG DOXPLQXP LV JLYHQ LQ WDEOH

Table 1-4.—Comparative Characteristics of Copper and Aluminum

+$5$7(5,67,6 233(5 $/80,180
7HQVLOH VWUHQJWK OELQ

7HQVLOH VWUHQJWK IRU VDPH
FRQGXFWLYLW OE

:HLJKW IRU VDPH FRQGXFWLYLW OE

URVV VHFWLRQ IRU VDPH FRQGXFWLYLW
0

RSSHU KDV D KLJKHU FRQGXFWLYLW WKDQ DOXPLQXP ,W LV PRUH GXFWLOH FDQ EH GUDZQ RXW

RSSHU KDV
UHODWLYHO KLJK WHQVLOH VWUHQJWK WKH JUHDWHVW VWUHVV D VXEVWDQFH FDQ EHDU DORQJ LWV OHQJWK ZLWKRXW WHDULQJ
DSDUW

,W FDQ DOVR EH HDVLO VROGHUHG +RZHYHU FRSSHU LV PRUH H[SHQVLYH DQG KHDYLHU WKDQ DOXPLQXP
$OWKRXJK DOXPLQXP KDV RQO DERXW SHUFHQW RI WKH FRQGXFWLYLW RI FRSSHU LWV OLJKWQHVV PDNHV ORQJ
VSDQV SRVVLEOH ,WV UHODWLYHO ODUJH GLDPHWHU IRU D JLYHQ FRQGXFWLYLW UHGXFHV FRURQD RURQD LV WKH
GLVFKDUJH RI HOHFWULFLW IURP WKH ZLUH ZKHQ LW KDV D KLJK SRWHQWLDO 7KH GLVFKDUJH LV JUHDWHU ZKHQ VPDOOHU
GLDPHWHU ZLUH LV XVHG WKDQ ZKHQ ODUJHU GLDPHWHU ZLUH LV XVHG +RZHYHU WKH UHODWLYHO ODUJH VL]H RI
DOXPLQXP IRU D JLYHQ FRQGXFWDQFH GRHV QRW SHUPLW WKH HFRQRPLFDO XVH RI DQ LQVXODWLRQ FRYHULQJ
Q14. State two advantages of using aluminum wire for carrying electricity over long distances.
Q15. State four advantages of copper over aluminum as a conductor.
TEMPERATURE COEFFICIENT
7KH UHVLVWDQFH RI SXUH PHWDOV VXFK DV VLOYHU FRSSHU DQG DOXPLQXP LQFUHDVHV DV WKH WHPSHUDWXUH
LQFUHDVHV +RZHYHU WKH UHVLVWDQFH RI VRPH DOORV VXFK DV FRQVWDQWDQ DQG PDQJDQLQ FKDQJHV YHU OLWWOH
DV WKH WHPSHUDWXUH FKDQJHV 0HDVXULQJ LQVWUXPHQWV XVH WKHVH DOORV EHFDXVH WKH UHVLVWDQFH RI WKH FLUFXLWV
PXVW UHPDLQ FRQVWDQW WR JHW DFFXUDWH PHDVXUHPHQWV
,Q WDEOH WKH UHVLVWDQFH RI D FLUFXODUPLOIRRW RI ZLUH WKH VSHFLILF UHVLVWDQFH

LV JLYHQ DW D VSHFLILF
WHPSHUDWXUH ž LQ WKLV FDVH ,W LV QHFHVVDU WR HVWDEOLVK D VWDQGDUG WHPSHUDWXUH $V ZH VWDWHG HDUOLHU
WKH UHVLVWDQFH RI SXUH PHWDOV LQFUHDVHV ZLWK DQ LQFUHDVH LQ WHPSHUDWXUH 7KHUHIRUH D WUXH EDVLV RI
FRPSDULVRQ FDQQRW EH PDGH XQOHVV WKH UHVLVWDQFHV RI DOO WKH VXEVWDQFHV EHLQJ FRPSDUHG DUH PHDVXUHG DW
WKH VDPH WHPSHUDWXUH 7KH DPRXQW RI LQFUHDVH LQ WKH UHVLVWDQFH RI D RKP VDPSOH RI WKH FRQGXFWRU SHU
GHJUHH ULVH LQ WHPSHUDWXUH DERYH ž LV FDOOHG WKH WHPSHUDWXUH FRHIILFLHQW RI UHVLVWDQFH )RU FRSSHU WKH
YDOXH LV DSSUR[LPDWHO RKP
$ OHQJWK RI FRSSHU ZLUH KDYLQJ D UHVLVWDQFH RI RKPV DW DQ LQLWLDO WHPSHUDWXUH RI ž ZLOO KDYH DQ
LQFUHDVH LQ UHVLVWDQFH RI × RU RKPV 7KLV DSSOLHV WR WKH HQWLUH OHQJWK RI ZLUH DQG IRU
HDFK GHJUHH RI WHPSHUDWXUH ULVH DERYH ž $ ž LQFUHDVH LQ UHVLVWDQFH LV DSSUR[LPDWHO × RU
RKPV 7KH WRWDO UHVLVWDQFH DW ž LV RU RKPV
Q16. Define the temperature coefficient of resistance.
Q17. What happens to the resistance of copper when it is heated?

CONDUCTOR INSULATION
7R EH XVHIXO DQG VDIH HOHFWULF FXUUHQW PXVW EH IRUFHG WR IORZ RQO ZKHUH LW LV QHHGHG ,W PXVW EH
FKDQQHOHG IURP WKH SRZHU VRXUFH WR D XVHIXO ORDG ,Q JHQHUDO FXUUHQWFDUULQJ FRQGXFWRUV PXVW QRW EH
DOORZHG WR FRPH LQ FRQWDFW ZLWK RQH DQRWKHU WKHLU VXSSRUWLQJ KDUGZDUH RU SHUVRQQHO ZRUNLQJ QHDU WKHP

7R DFFRPSOLVK WKLV FRQGXFWRUV DUH FRDWHG RU ZUDSSHG ZLWK YDULRXV PDWHULDOV 7KHVH PDWHULDOV KDYH VXFK D
KLJK UHVLVWDQFH WKDW WKH DUH IRU DOO SUDFWLFDO SXUSRVHV QRQFRQGXFWRUV 1RQFRQGXFWRUV DUH JHQHUDOO
UHIHUUHG WR DV LQVXODWRUV RU LQVXODWLQJ PDWHULDO
2QO WKH QHFHVVDU PLQLPXP DPRXQW RI LQVXODWLRQ LV DSSOLHG WR DQ SDUWLFXODU WSH RI FRQGXFWRU
GHVLJQHG WR GR D SDUWLFXODU MRE 7KLV LV GRQH EHFDXVH RI VHYHUDO IDFWRUV 7KH H[SHQVH VWLIIHQLQJ HIIHFW DQG
D YDULHW RI SKVLFDO DQG HOHFWULFDO FRQGLWLRQV XQGHU ZKLFK WKH FRQGXFWRUV DUH RSHUDWHG PXVW EH WDNHQ LQWR
DFFRXQW 7KHUHIRUH WKHUH DUH D YDULHW RI LQVXODWHG FRQGXFWRUV DYDLODEOH WR PHHW WKH UHTXLUHPHQWV RI DQ
MRE
7ZR IXQGDPHQWDO SURSHUWLHV RI LQVXODWLQJ PDWHULDOV WKDW LV UXEEHU JODVV DVEHVWRV RU SODVWLF

DUH
LQVXODWLRQ UHVLVWDQFH DQG GLHOHFWULF VWUHQJWK 7KHVH DUH WZR HQWLUHO GLIIHUHQW DQG GLVWLQFW SURSHUWLHV
INSULATION RESISTANCE
,QVXODWLRQ UHVLVWDQFH LV WKH UHVLVWDQFH WR FXUUHQW OHDNDJH WKURXJK WKH LQVXODWLRQ PDWHULDOV ,QVXODWLRQ
UHVLVWDQFH FDQ EH PHDVXUHG ZLWK D PHJJHU ZLWKRXW GDPDJLQJ WKH LQVXODWLRQ ,QIRUPDWLRQ VR REWDLQHG LV D
XVHIXO JXLGH LQ DSSUDLVLQJ WKH JHQHUDO FRQGLWLRQ RI LQVXODWLRQ OHDQ GU LQVXODWLRQ KDYLQJ FUDFNV RU RWKHU
IDXOWV PD VKRZ D KLJK YDOXH RI LQVXODWLRQ UHVLVWDQFH EXW ZRXOG QRW EH VXLWDEOH IRU XVH
DIELECTRIC STRENGTH
'LHOHFWULF VWUHQJWK LV WKH DELOLW RI DQ LQVXODWRU WR ZLWKVWDQG SRWHQWLDO GLIIHUHQFH ,W LV XVXDOO
H[SUHVVHG LQ WHUPV RI WKH YROWDJH DW ZKLFK WKH LQVXODWLRQ IDLOV EHFDXVH RI WKH HOHFWURVWDWLF VWUHVV
0D[LPXP GLHOHFWULF VWUHQJWK YDOXHV FDQ EH PHDVXUHG RQO E UDLVLQJ WKH YROWDJH RI D 7(67 6$03/(
XQWLO WKH LQVXODWLRQ EUHDNV GRZQ
Q18. Compare the resistance of a conductor to that of an insulator.
Q19. State two fundamental properties of insulating materials.
Q20. Define insulation resistance.
Q21. Define dielectric strength.
Q22. How is the dielectric strength of an insulator determined?
TYPES OF INSULATION
7KH LQVXODWLQJ PDWHULDOV GLVFXVVHG LQ WKH QH[W SDUDJUDSKV DUH FRPPRQO XVHG LQ 1DY HOHFWULFDO DQG
HOHFWURQLF HTXLSPHQW
Rubber
2QH RI WKH PRVW FRPPRQ WSHV RI LQVXODWLRQ LV UXEEHU 7KH YROWDJH WKDW PD EH DSSOLHG WR D UXEEHU
FRYHUHG FRQGXFWRU LV GHSHQGHQW RQ WKH WKLFNQHVV DQG WKH TXDOLW RI WKH UXEEHU FRYHULQJ 2WKHU IDFWRUV
EHLQJ HTXDO WKH WKLFNHU WKH LQVXODWLRQ WKH KLJKHU PD EH WKH DSSOLHG YROWDJH 5XEEHU LQVXODWLRQ LV
QRUPDOO XVHG IRU ORZ RU PHGLXPUDQJH YROWDJH )LJXUH VKRZV WZR WSHV RI UXEEHUFRYHUHG ZLUH
2QH LV D WZRFRQGXFWRU FDEOH LQ ZKLFK HDFK VWUDQGHG FRQGXFWRU LV FRYHUHG ZLWK UXEEHU LQVXODWLRQ WKH
RWKHU LV D VLQJOH VROLG FRQGXFWRU ,Q HDFK FDVH WKH UXEEHU VHUYHV WKH VDPH SXUSRVH WR FRQILQH WKH FXUUHQW
WR LWV FRQGXFWRU

Figure 1-7.—Rubber insulation.
5HIHUULQJ WR WKH HQODUJHG FURVVVHFWLRQDO YLHZ LQ ILJXUH QRWH WKDW D WKLQ FRDWLQJ RI WLQ VHSDUDWHV
WKH FRSSHU FRQGXFWRU IURP WKH UXEEHU LQVXODWLRQ ,I WKH WKLQ FRDWLQJ RI WLQ ZHUH QRW XVHG D FKHPLFDO DFWLRQ
ZRXOG WDNH SODFH DQG WKH UXEEHU ZRXOG EHFRPH VRIW DQG JXPP ZKHUH LW PDNHV FRQWDFW ZLWK WKH FRSSHU
:KHQ VPDOO VROLG RU VWUDQGHG FRQGXFWRUV DUH XVHG D ZLQGLQJ RI FRWWRQ WKUHDGV LV DSSOLHG EHWZHHQ WKH
FRQGXFWRUV DQG WKH UXEEHU LQVXODWLRQ
CODE-GRADED RUBBER²RGHJUDGHG UXEEHU LV WKH VWDQGDUG WKDW WKH 1DWLRQDO (OHFWULFDO
RGH 1(

KDV DGRSWHG DV WKH PLQLPXP UHTXLUHPHQWV IRU UXEEHU LQVXODWLRQ DV VSHFLILHG E
8QGHUZULWHUV
/DERUDWRULHV ,Q WKLV FRGH VVWHP WKH OHWWHU 5 LQGLFDWHV WKH XVH RI D UXEEHU LQVXODWRU 7SH
5 VLJQLILHV WKDW WKH ZLUH LV UXEEHU FRDWHG
7KH 1( FRGHV 7SH 5+ DQG 7SH 5++ VLJQLI D UXEEHU KHDWUHVLVWDQW FRPSRXQG 7SH 5:
VLJQLILHV D UXEEHU PRLVWXUHUHVLVWDQW FRPSRXQG $ 7SH 5+: VLJQLILHV D UXEEHU KHDW DQG PRLVWXUH
UHVLVWDQW FRPSRXQG 7SH 5+: LV DSSURYHG IRU XVH LQ ZHW RU GU ORFDWLRQV DW D PD[LPXP FRQGXFWRU
WHPSHUDWXUH RI ž 1HRSUHQH D ORZYROWDJH FRPSRXQG LV WKH RQH H[FHSWLRQ WR 7SH 5+: $OWKRXJK
QRW D UXEEHU FRPSRXQG QHRSUHQH PHHWV WKH UHTXLUHPHQWV RI 8QGHUZULWHUV
/DERUDWRULHV DQG ZDV
GHVLJQDWHG 7SH 5+:
LATEX RUBBER²/DWH[ UXEEHU LV D KLJKJUDGH FRPSRXQG FRQVLVWLQJ RI SHUFHQW XQPLOOHG
JUDLQOHVV UXEEHU 7KHUH DUH WZR GHVLJQDWLRQV IRU WKLV WSH RI LQVXODWLRQ 7SH 58+ DQG 7SH 58: 7SH
58+ UXEEHU XQPLOOHG KHDWUHVLVWDQW

LV XVHG LQ GU ORFDWLRQV ZKHQ WKH FRQGXFWRU WHPSHUDWXUH GRHV QRW
H[FHHG ž 7SH 58: UXEEHU XQPLOOHG PRLVWXUHUHVLVWDQW

LV XVHG LQ ZHW ORFDWLRQV ZKHQ WKH
FRQGXFWRU GRHV QRW H[FHHG ž
SILICONE²6LOLFRQH LV D UXEEHU FRPSRXQG WKDW GRHV QRW FDUU WKH 5 GHVLJQDWRU IRU PDQ RI LWV
DSSOLFDWLRQV $Q H[DPSOH RI WKLV LV 7SH 6$ VLOLFRQHDVEHVWRV

,Q 7SH 6$ WKH LQVXODWRU DURXQG WKH
FRQGXFWRU LV VLOLFRQH UXEEHU EXW WKH RXWHU FRYHULQJ PXVW FRQVLVW RI KHDY JODVV DVEHVWRVJODVV RU
DVEHVWRV EUDLGLQJ WUHDWHG ZLWK D KHDW IODPH DQG PRLVWXUHUHVLVWDQW FRPSRXQG
Q23. What is the purpose of coating a copper conductor with tin when rubber insulation is used?

Plastics
3ODVWLF LV RQH RI WKH PRUH FRPPRQO XVHG WSHV RI LQVXODWLQJ PDWHULDO IRU HOHFWULFDO FRQGXFWRUV ,W KDV
JRRG LQVXODWLQJ IOH[LELOLW DQG PRLVWXUHUHVLVWDQW TXDOLWLHV $OWKRXJK WKHUH DUH PDQ WSHV RI SODVWLF
LQVXODWLQJ PDWHULDOV WKHUPRSODVWLF LV RQH RI WKH PRVW FRPPRQ :LWK WKH XVH RI WKHUPRSODVWLF WKH
FRQGXFWRU WHPSHUDWXUH FDQ EH KLJKHU WKDQ ZLWK VRPH RWKHU WSHV RI LQVXODWLQJ PDWHULDOV ZLWKRXW GDPDJH
WR WKH LQVXODWLQJ TXDOLW RI WKH PDWHULDO 3ODVWLF LQVXODWLRQ LV QRUPDOO XVHG IRU ORZ RU PHGLXPUDQJH
YROWDJH
7KH GHVLJQDWRUV XVHG ZLWK WKHUPRSODVWLFV DUH PXFK OLNH WKRVH XVHG ZLWK UXEEHU LQVXODWRUV 7KH
IROORZLQJ OHWWHUV DUH XVHG ZKHQ GHDOLQJ ZLWK 1( WSH GHVLJQDWRUV IRU WKHUPRSODVWLFV

/HWWHU 'HVLJQDWHV
7 7KHUPRSODVWLF
+ +HDWUHVLVWDQW
: 0RLVWXUHUHVLVWDQW
$ $VEHVWRV
1 2XWHU QORQ MDFNHW
0 2LOUHVLVWDQW

)RU H[DPSOH D 1( GHVLJQDWRU RI 7SH 7+:1 ZRXOG LQGLFDWH WKHUPRSODVWLF KHDW DQG PRLVWXUH
UHVLVWDQW ZLWK DQ RXWHU QORQ MDFNHW
Varnished Cambric
9DUQLVKHG FDPEULF LQVXODWLRQ FDQ ZLWKVWDQG PXFK KLJKHU WHPSHUDWXUHV WKDQ UXEEHU LQVXODWLRQ
9DUQLVKHG FDPEULF LV FRWWRQ FORWK WKDW KDV EHHQ FRDWHG ZLWK DQ LQVXODWLQJ YDUQLVK )LJXUH VKRZV D
FDEOH FRYHUHG ZLWK YDUQLVKHG FDPEULF LQVXODWLRQ 7KH YDUQLVKHG FDPEULF LV LQ WDSH IRUP DQG LV ZRXQG
DURXQG WKH FRQGXFWRU LQ ODHUV $Q RLO FRPSRXQG LV DSSOLHG EHWZHHQ HDFK ODHU RI WKH WDSH WR SUHYHQW
ZDWHU IURP VHHSLQJ WKURXJK WKH LQVXODWLRQ ,W DOVR DFWV DV D OXEULFDQW EHWZHHQ WKH ODHUV RI WDSH VR WKH
ZLOO VOLGH RYHU HDFK RWKHU ZKHQ WKH FDEOH LV EHQW

Figure 1-8.—Varnished cambric insulation.

DPEULF LQVXODWLRQ LV XVHG RQ H[WUHPHO KLJKYROWDJH FRQGXFWRUV XVHG LQ VXEVWDWLRQV DQG
SRZHUKRXVHV ,W LV DOVR XVHG LQ RWKHU ORFDWLRQV VXEMHFWHG WR KLJK WHPSHUDWXUHV ,Q DGGLWLRQ LW LV XVHG RQ WKH
FRLOV DQG OHDGV RI KLJKYROWDJH JHQHUDWRUV 7UDQVIRUPHU OHDGV DOVR XVH WKLV LQVXODWLRQ EHFDXVH LW LV
XQDIIHFWHG E RLOV RU JUHDVH DQG KDV KLJK GLHOHFWULF VWUHQJWK 9DUQLVKHG FDPEULF DQG SDSHU LQVXODWLRQ IRU
FDEOHV DUH WKH WZR WSHV RI LQVXODWLQJ PDWHULDOV PRVW ZLGHO XVHG DW YROWDJHV DERYH YROWV 6XFK
FDEOH LV DOZDV OHDG FRYHUHG WR NHHS RXW PRLVWXUH

Extruded Polytetrafluoroethylene
([WUXGHG SROWHWUDIOXRURHWKOHQH LV D KLJKWHPSHUDWXUH LQVXODWLRQ XVHG H[WHQVLYHO LQ DLUFUDIW DQG
HTXLSPHQW LQVWDOODWLRQV ,W ZLOO QRW EXUQ EXW ZLOO YDSRUL]H ZKHQ VXEMHFWHG WR LQWHQVH KHDW RQGXFWRUV IRU
KLJK WHPSHUDWXUHV XVH D QLFNHO FRDWLQJ UDWKHU WKDQ WLQ RU VLOYHU WR SUHYHQW R[LGDWLRQ 1LFNHOFRDWHG ZLUH LV
PRUH GLIILFXOW WR VROGHU EXW PDNHV VDWLVIDFWRU FRQQHFWLRQV ZLWK SURSHU VROGHULQJ WHFKQLTXHV
WARNING
Avoid breathing the vapors from extruded polytetrafluoroethylene insulation
when it is heated. Symptoms of overexposure are dizziness or headaches. These
symptoms disappear upon exposure to fresh air.
Q24. What safety precaution should you take when working with extruded polytetrafluoroethylene
insulated wiring?
Fluorinated Ethylene Propylene (FEP)
)(3 KDV SURSHUWLHV VLPLODU WR H[WUXGHG SROWHWUDIOXRURHWKOHQH EXW ZLOO PHOW DW VROGHULQJ
WHPSHUDWXUHV ,W LV UDWHG DW ž DQG LV WKHUHIRUH FRQVLGHUHG D KLJKWHPSHUDWXUH LQVXODWLRQ 7KHUH DUH QR
NQRZQ WR[LF YDSRUV IURP )(3 RPPRQVHQVH SUDFWLFH KRZHYHU UHTXLUHV WKDW RX SURYLGH DGHTXDWH
YHQWLODWLRQ GXULQJ DQ VROGHULQJ RSHUDWLRQ
Asbestos
$VEHVWRV LQVXODWLRQ ZDV XVHG H[WHQVLYHO LQ WKH SDVW IRU KLJKWHPSHUDWXUH LQVXODWLRQ 7RGD LW LV
VHOGRP XVHG E WKH 1DY 0DQ QDYDO VKLSV DQG DLUFUDIW KRZHYHU VWLOO FRQWDLQ DVEHVWRVLQVXODWHG ZLULQJ
$ERDUG VKLS WKLV LV SDUWLFXODUO WUXH LQ JDOOH DQG ODXQGU HTXLSPHQW 7KH UHDVRQ IRU GLVFRQWLQXLQJ WKH
XVH RI DVEHVWRV DV DQ LQVXODWRU LV WKDW EUHDWKLQJ DVEHVWRV ILEHUV FDQ SURGXFH VHYHUH OXQJ GDPDJH ,W FDQ
UHQGHU RX GLVDEOHG RU FDXVH IDWDO ILEURVLV RI WKH OXQJV $VEHVWRV LV DOVR D IDFWRU LQ WKH GHYHORSPHQW RI
FDQFHU LQ WKH JDVWURLQWHVWLQDO WUDFW 6DIHW SUHFDXWLRQV FRQFHUQLQJ DVEHVWRV ZLOO EH FRYHUHG LQ PRUH GHWDLO
DW WKH HQG RI FKDSWHU
WARNING
Avoid inhalation of asbestos fibers. Asbestos fibers have been found to cause
severe lung damage (asbestosis) and cancer of the gastrointestinal tract. Follow
Navy safety precautions when working with all asbestos products.
2QH WSH RI DVEHVWRVFRYHUHG ZLUH LV VKRZQ LQ ILJXUH ,W FRQVLVWV RI VWUDQGHG FRSSHU FRQGXFWRUV
FRYHUHG ZLWK IHOWHG DVEHVWRV 7KH ZLUH LV LQ WXUQ FRYHUHG ZLWK DVEHVWRV EUDLG 7KLV WSH RI ZLUH LV XVHG LQ
PRWLRQSLFWXUH SURMHFWRUV DUF ODPSV VSRWOLJKWV KHDWLQJ HOHPHQW OHDGV DQG VR IRUWK

Figure 1-9.—Asbestos Insulation.

$QRWKHU WSH RI DVEHVWRVFRYHUHG FDEOH LV VKRZQ LQ ILJXUH ,W LV FRPELQDWLRQ RI DVEHVWRV DQG
YDUQLVKHG FDPEULF 7KLV WSH RI LQVXODWLRQ VHUYHV DV OHDGV IRU PRWRUV DQG WUDQVIRUPHUV WKDW VRPHWLPHV
PXVW RSHUDWH LQ KRW GDPS ORFDWLRQV 7KH YDUQLVKHG FDPEULF FRYHUV WKH LQQHU ODHU RI IHOWHG DVEHVWRV 7KLV
SUHYHQWV PRLVWXUH IURP UHDFKLQJ WKH LQQHUPRVW ODHU RI DVEHVWRV $VEHVWRV ORVHV LWV LQVXODWLQJ SURSHUWLHV
ZKHQ LW EHFRPHV ZHW ,W ZLOO LQ IDFW EHFRPH D FRQGXFWRU 9DUQLVKHG FDPEULF SUHYHQWV WKLV IURP
KDSSHQLQJ EHFDXVH LW UHVLVWV PRLVWXUH $OWKRXJK WKLV LQVXODWLRQ ZLOO ZLWKVWDQG VRPH PRLVWXUH LW VKRXOG
QRW EH XVHG RQ FRQGXFWRUV WKDW PD DW WLPHV EH SDUWLDOO LPPHUVHG LQ ZDWHU 8QGHU WKRVH FLUFXPVWDQFHV
WKH LQVXODWLRQ PXVW EH SURWHFWHG ZLWK DQ RXWHU OHDG VKHDWK

Figure 1-10.—Asbestos and varnished cambric insulation.
7KH 1( KDV GHVLJQDWRUV IRU HLJKW WSHV RI DVEHVWRV ZLUH 7KH GHVLJQDWRUV DQG D GHVFULSWLRQ RI HDFK
DUH OLVWHG EHORZ

7SH $ 1RQLPSUHJQDWHG DVEHVWRV ZLWKRXW DQ DVEHVWRV EUDLG
7SH $$ 1RQLPSUHJQDWHG DVEHVWRV ZLWK DQ RXWHU DVEHVWRV EUDLG RU JODVV
7SH $, ,PSUHJQDWHG DVEHVWRV ZLWKRXW DQ DVEHVWRV EUDLG
7SH $,$ ,PSUHJQDWHG DVEHVWRV ZLWK DQ RXWHU DVEHVWRV EUDLG RU JODVV
7SH $9$ $VEHVWRV YDUQLVKFDPEULF LQVXODWLRQ ZLWK DQ RXWHU DVEHVWRV EUDLG RU JODVV
7SH $9/ $VEHVWRV YDUQLVKFDPEULF LQVXODWLRQ ZLWK DQ RXWHU DVEHVWRV EUDLG FRYHUHG ZLWK D OHDG
VKHDWK
7SH $9% $VEHVWRV YDUQLVKFDPEULF LQVXODWLRQ ZLWK DQ RXWHU IODPHUHWDUGDQW FRWWRQ EUDLG
7SH 6$ 6LOLFRQH UXEEHU LQVXODWHG ZLWK RXWHU KHDY JODVV DVEHVWRVJODVV RU DVEHVWRV EUDLG

Q25. State the reasons that the Navy is getting away from the use of asbestos insulation.
Q26. State what happens to the insulating characteristics of asbestos when it gets wet.
Paper
3DSHU KDV OLWWOH LQVXODWLRQ YDOXH DORQH +RZHYHU ZKHQ LPSUHJQDWHG ZLWK D KLJK JUDGH RI PLQHUDO RLO
LW VHUYHV DV D VDWLVIDFWRU LQVXODWLRQ IRU H[WUHPHO KLJKYROWDJH FDEOHV 7KH RLO KDV D KLJK GLHOHFWULF
VWUHQJWK DQG WHQGV WR SUHYHQW EUHDNGRZQ RI WKH SDSHU LQVXODWLRQ 7KH SDSHU PXVW EH WKRURXJKO VDWXUDWHG
ZLWK WKH RLO 7KH WKLQ SDSHU WDSH LV ZUDSSHG LQ PDQ ODHUV DURXQG WKH FRQGXFWRUV DQG WKHQ VRDNHG ZLWK
RLO
7KH WKUHHFRQGXFWRU FDEOH VKRZQ LQ ILJXUH FRQVLVWV RI SDSHU LQVXODWLRQ RQ HDFK FRQGXFWRU ,W KDV
D VSLUDOO ZUDSSHG QRQPDJQHWLF PHWDOOLF WDSH RYHU WKH LQVXODWLRQ 7KH VSDFH EHWZHHQ FRQGXFWRUV LV ILOOHG
ZLWK D VXLWDEOH VSDFHU WR URXQG RXW WKH FDEOH $QRWKHU QRQPDJQHWLF PHWDO WDSH LV XVHG WR VHFXUH WKH HQWLUH

FDEOH 2YHU WKLV D OHDG VKHDWK LV DSSOLHG 7KLV WSH RI FDEOH LV XVHG RQ YROWDJHV IURP YROWV WR
YROWV

Figure 1-11.—Paper-insulated power cables.

Q27. What are the most common insulators used for extremely high voltages?
Silk and Cotton
,Q FHUWDLQ WSHV RI FLUFXLWV IRU H[DPSOH FRPPXQLFDWLRQV FLUFXLWV

D ODUJH QXPEHU RI FRQGXFWRUV DUH
QHHGHG SHUKDSV DV PDQ DV VHYHUDO KXQGUHG )LJXUH VKRZV D FDEOH FRQWDLQLQJ PDQ FRQGXFWRUV
(DFK LV LQVXODWHG IURP WKH RWKHUV E VLON DQG FRWWRQ WKUHDG %HFDXVH WKH LQVXODWLRQ LQ WKLV WSH RI FDEOH LV
QRW VXEMHFWHG WR KLJK YROWDJH WKH XVH RI WKLQ ODHUV RI VLON DQG FRWWRQ LV VDWLVIDFWRU

Figure 1-12.—Silk and cotton Insulation.
6LON DQG FRWWRQ LQVXODWLRQ NHHSV WKH VL]H RI WKH FDEOH VPDOO HQRXJK WR EH KDQGOHG HDVLO 7KH VLON DQG
FRWWRQ WKUHDGV DUH ZUDSSHG DURXQG WKH LQGLYLGXDO FRQGXFWRUV LQ UHYHUVH GLUHFWLRQV 7KH FRYHULQJ LV WKHQ
LPSUHJQDWHG ZLWK D VSHFLDO ZD[ FRPSRXQG
Enamel
7KH ZLUH XVHG RQ WKH FRLOV RI PHWHUV UHODV VPDOO WUDQVIRUPHUV PRWRU ZLQGLQJV DQG VR IRUWK LV
FDOOHG PDJQHW ZLUH 7KLV ZLUH LV LQVXODWHG ZLWK DQ HQDPHO FRDWLQJ 7KH HQDPHO LV D VQWKHWLF FRPSRXQG RI
FHOOXORVH DFHWDWH ZRRG SXOS DQG PDJQHVLXP

,Q WKH PDQXIDFWXULQJ SURFHVV WKH EDUH ZLUH LV SDVVHG
WKURXJK D VROXWLRQ RI KRW HQDPHO DQG WKHQ FRROHG 7KLV SURFHVV LV UHSHDWHG XQWLO WKH ZLUH DFTXLUHV IURP
WR FRDWLQJV 7KLFNQHVV IRU WKLFNQHVV HQDPHO KDV KLJKHU GLHOHFWULF VWUHQJWK WKDQ UXEEHU ,W LV QRW

SUDFWLFDO IRU ODUJH ZLUHV EHFDXVH RI WKH H[SHQVH DQG EHFDXVH WKH LQVXODWLRQ LV UHDGLO IUDFWXUHG ZKHQ ODUJH
ZLUHV DUH EHQW
)LJXUH VKRZV DQ HQDPHOFRDWHG ZLUH (QDPHO LV WKH WKLQQHVW LQVXODWLQJ FRDWLQJ WKDW FDQ EH
DSSOLHG WR ZLUHV +HQFH HQDPHOLQVXODWHG PDJQHW ZLUH PDNHV VPDOOHU FRLOV (QDPHOHG ZLUH LV VRPHWLPHV
FRYHUHG ZLWK RQH RU PRUH ODHUV RI FRWWRQ WR SURWHFW WKH HQDPHO IURP QLFNV FXWV RU DEUDVLRQV

Figure 1-13.—Enamel Insulation.
Q28. What is the common name for enamel-insulated wire?
Mineral Insulated
0LQHUDOLQVXODWHG 0,

FDEOH ZDV GHYHORSHG WR PHHW WKH QHHGV RI D QRQFRPEXVWLEOH KLJK KHDW
UHVLVWDQW DQG ZDWHUUHVLVWDQW FDEOH 0, FDEOH KDV IURP RQH WR VHYHQ HOHFWULFDO FRQGXFWRUV 7KHVH
FRQGXFWRUV DUH LQVXODWHG LQ D KLJKO FRPSUHVVHG PLQHUDO QRUPDOO PDJQHVLXP R[LGH DQG VHDOHG LQ D
OLTXLGWLJKW JDVWLJKW PHWDOOLF WXEH QRUPDOO PDGH RI VHDPOHVV FRSSHU ILJXUH

Figure 1-14.—Two-conductor mineral-insulated (MI) cable.

CONDUCTOR PROTECTION
:LUHV DQG FDEOHV DUH JHQHUDOO VXEMHFW WR DEXVH 7KH WSH DQG DPRXQW RI DEXVH GHSHQGV RQ KRZ DQG
ZKHUH WKH DUH LQVWDOOHG DQG WKH PDQQHU LQ ZKLFK WKH DUH XVHG DEOHV EXULHG GLUHFWO LQ WKH JURXQG PXVW
UHVLVW PRLVWXUH FKHPLFDO DFWLRQ DQG DEUDVLRQ :LUHV LQVWDOOHG LQ EXLOGLQJV PXVW EH SURWHFWHG DJDLQVW
PHFKDQLFDO LQMXU DQG RYHUORDGLQJ :LUHV VWUXQJ RQ FURVVDUPV RQ SROHV PXVW EH NHSW IDU HQRXJK DSDUW VR
WKDW WKH ZLUHV GR QRW WRXFK 6QRZ LFH DQG VWURQJ ZLQGV PDNH LW QHFHVVDU WR XVH FRQGXFWRUV KDYLQJ KLJK
WHQVLOH VWUHQJWK DQG VXEVWDQWLDO IUDPH VWUXFWXUHV

*HQHUDOO H[FHSW IRU RYHUKHDG WUDQVPLVVLRQ OLQHV ZLUHV RU FDEOHV DUH SURWHFWHG E VRPH IRUP RI
FRYHULQJ 7KH FRYHULQJ PD EH VRPH WSH RI LQVXODWRU OLNH UXEEHU RU SODVWLF 2YHU WKLV DGGLWLRQDO ODHUV
RI ILEURXV EUDLG RU WDSH PD EH XVHG DQG WKHQ FRYHUHG ZLWK D ILQLVK RU VDWXUDWHG ZLWK D SURWHFWLYH FRDWLQJ
,I WKH ZLUH RU FDEOH LV LQVWDOOHG ZKHUH LW LV OLNHO WR UHFHLYH URXJK WUHDWPHQW D PHWDOOLF FRDW VKRXOG EH
DGGHG
7KH PDWHULDOV XVHG WR PDNH XS WKH SURWHFWLRQ IRU D ZLUH RU FDEOH DUH JURXSHG LQWR RQH RI WZR
FDWHJRULHV QRQPHWDOOLF RU PHWDOOLF
Q29. If a cable is installed where it receives rough treatment, what should be added?
NONMETALLIC PROTECTION
7KH FDWHJRU RI QRQPHWDOOLF SURWHFWLYH FRYHULQJV LV GLYLGHG LQWR WKUHH DUHDV 7KHVH DUHDV DUH

DFFRUGLQJ WR WKH PDWHULDO XVHG DV WKH FRYHULQJ

DFFRUGLQJ WR WKH VDWXUDQW LQ ZKLFK WKH FRYHULQJ ZDV
LPSUHJQDWHG DQG

DFFRUGLQJ WR WKH H[WHUQDO ILQLVK RQ WKH ZLUH RU FDEOH 7KHVH WKUHH DUHDV UHIOHFW WKUHH
GLIIHUHQW PHWKRGV RI SURWHFWLQJ WKH ZLUH RU FDEOH 7KHVH PHWKRGV DOORZ VRPH ZLUH RU FDEOH WR EH FODVVLILHG
XQGHU PRUH WKDQ RQH FDWHJRU 0RVW RI WKH WLPH KRZHYHU WKH ZLUH RU FDEOH ZLOO EH FODVVLILHG EDVHG XSRQ
WKH PDWHULDO XVHG DV WKH FRYHULQJ UHJDUGOHVV RI ZKHWKHU RU QRW D VDWXUDQW RU ILQLVK LV DSSOLHG
0DQ WSHV RI QRQPHWDOOLF PDWHULDOV DUH XVHG WR SURWHFW ZLUHV DQG FDEOHV )LEURXV EUDLG LV E IDU WKH
PRVW FRPPRQ DQG ZLOO EH GLVFXVVHG ILUVW
Fibrous Braid
)LEURXV EUDLG LV XVHG H[WHQVLYHO DV D SURWHFWLYH FRYHULQJ IRU FDEOHV 7KLV EUDLG LV ZRYHQ RYHU WKH
LQVXODWLRQ WR IRUP D FRQWLQXRXV FRYHULQJ ZLWKRXW MRLQWV ILJXUH

7KH EUDLG LV JHQHUDOO VDWXUDWHG
ZLWK DVSKDOW SDLQW RU YDUQLVK WR JLYH DGGHG SURWHFWLRQ DJDLQVW PRLVWXUH IODPH ZHDWKHULQJ RLO RU DFLG
$GGLWLRQDOO WKH RXWVLGH EUDLG LV RIWHQ JLYHQ D ILQLVK RI VWHDULQ SLWFK DQG PLFD IODNHV SDLQW ZD[ ODFTXHU
RU YDUQLVK GHSHQGLQJ RQ WKH HQYLURQPHQW ZKHUH WKH FDEOH LV WR EH XVHG

Figure 1-15.—Fibrous braid covering.
7KH PRVW FRPPRQ WSH RI ILEURXV EUDLG LV ZRYHQ IURP OLJKW VWDQGDUG RU KHDY FRWWRQ DUQ RWWRQ
DUQ FRPHV LQ GLIIHUHQW FRORUV ZKLFK DOORZV FRORUFRGLQJ RI WKH LQGLYLGXDO FRQGXFWRUV RWWRQ ZLOO QRW
ZLWKVWDQG DOO WKH SRVVLEOH HQYLURQPHQWV LQ ZKLFK D FDEOH PD EH ODLG 2WKHU PDWHULDOV FXUUHQWO EHLQJ
XVHG WR PDNH ILEURXV EUDLG DUH JOD]HG FRWWRQ VHLQH WZLQH RU KDZVHU FRUG KHPS SDSHU DQG FRWWRQ MXWH
DVEHVWRV VLON UDRQ DQG ILEURXV JODVV 7KH FKRLFH RI ZKLFK PDWHULDO WR XVH GHSHQGV RQ WKH VWUHQJWK
QHHGHG LQ WKH FDEOH DV ZHOO DV KRZ UHVLVWDQW LW PXVW EH WR LWV HQYLURQPHQW
Fibrous Tape
)LEURXV WDSH FRYHULQJV DUH IUHTXHQWO XVHG DV D SDUW RI WKH SURWHFWLYH FRYHULQJ RI FDEOHV 7KH PDWHULDO
RI WDSH FRYHULQJV LV PDGH LQWR WKH WDSH EHIRUH DSSOLFDWLRQ WR WKH FDEOH 7KH PDWHULDO LQ DUQV IRU EUDLG

FRYHULQJ LV ZRYHQ LQWR IDEULF GXULQJ WKH DSSOLFDWLRQ WR WKH FDEOH :KHQ WDSH FRYHULQJ LV XVHG LW LV
ZUDSSHG KHOLFDOO DURXQG WKH FDEOH ZLWK HDFK WXUQ RYHUODSSLQJ WKH SUHYLRXV WXUQ
7KH PRVW FRPPRQ WSHV RI ILEURXV WDSH DUH UXEEHUILOOHG FORWK WDSH DQG D FRPELQDWLRQ RI FRWWRQ
FORWK DQG UXEEHU ([FHSW IRU GXFW WDSH WDSH FRYHULQJ LV QHYHU XVHG DV WKH RXWHU FRYHULQJ RQ D FDEOH 7DSH
FRYHULQJV DUH XVHG GLUHFWO RYHU WKH LQVXODWLRQ RI LQGLYLGXDO FRQGXFWRUV DQG IRU WKH LQQHU FRYHULQJ RYHU
WKH DVVHPEOHG FRQGXFWRUV RI D PXOWLFRQGXFWRU FDEOH )UHTXHQWO WDSH FRYHULQJV DUH XVHG XQGHU WKH VKHDWK
RI D OHDGVKHDWKHG FDEOH 'XFW WDSH ZKLFK LV PDGH RI KHDY FDQYDV ZHEELQJ VDWXUDWHG ZLWK DQ DVSKDOW
FRPSRXQG LV RIWHQ XVHG RYHU D OHDGVKHDWKHG FDEOH IRU SURWHFWLRQ DJDLQVW FRUURVLRQ DQG PHFKDQLFDO
LQMXU
Q30. How many categories of nonmetallic protective coverings are there?
Q31. What is the most common type of nonmetallic material used to protect wires and cables?
Q32. What are the most common types of fibrous tape?
Woven Covers
:RYHQ FRYHUV FRPPRQO FDOOHG ORRP DUH XVHG ZKHQ H[FHSWLRQDO DEUDVLRQUHVLVWDQW TXDOLWLHV DUH
UHTXLUHG 7KHVH FRYHUV DUH FRPSRVHG RI WKLFN KHDY ORQJILEHUHG FRWWRQ DUQV ZRYHQ DURXQG WKH FDEOH LQ
D FLUFXODU ORRP PXFK OLNH WKDW XVHG RQ D ILUH KRVH 7KH DUH QRW EUDLGV DOWKRXJK EUDLG FRYHULQJ DUH DOVR
ZRYHQ WKH DUH GHVLJQDWHG GLIIHUHQWO
Rubber and Synthetic Coverings
5XEEHU DQG VQWKHWLF FRYHULQJV DUH QRW VWDQGDUGL]HG 'LIIHUHQW PDQXIDFWXUHV KDYH WKHLU RZQ VSHFLDO
FRPSRXQGV GHVLJQDWHG E LQGLYLGXDO WUDGH QDPHV 7KHVH FRPSRXQGV DUH GLIIHUHQW IURP WKH UXEEHU
FRPSRXQGV XVHG WR LQVXODWH FDEOH 7KHVH FRPSRXQGV KDYH EHHQ SHUIHFWHG QRW IRU LQVXODWLRQ TXDOLWLHV EXW
IRU UHVLVWDQFH WR DEUDVLRQ PRLVWXUH RLO JDVROLQH DFLGV HDUWK VROXWLRQV DQG DONDOLHV 1RQH RI WKHVH
FRYHULQJV ZLOO SURYLGH SURWHFWLRQ DJDLQVW DOO WSHV RI H[SRVXUH (DFK FRYHULQJ KDV LWV RZQ SDUWLFXODU
OLPLWDWLRQV DQG TXDOLILFDWLRQV
Jute and Asphalt Coverings
-XWH DQG DVSKDOW FRYHULQJV DUH FRPPRQO XVHG DV D FXVKLRQ EHWZHHQ FDEOH LQVXODWLRQ DQG PHWDOOLF
DUPRU )UHTXHQWO WKH DUH DOVR XVHG DV D FRUURVLYHUHVLVWDQW FRYHULQJ RYHU D OHDG VKHDWK RU PHWDOOLF
DUPRU -XWH DQG DVSKDOW FRYHULQJV FRQVLVW RI DVSKDOWLPSUHJQDWHG MXWH DUQ KHOLZUDSSHG DURXQG WKH FDEOH
RU RI DOWHUQDWH ODHUV RI DVSKDOWLPSUHJQDWHG MXWH DUQ 7KHVH FRYHULQJV VHUYH DV D ZHDWKHUSURRILQJ
Unspun Felted Cotton
8QVSXQ IHOWHG FRWWRQ LV FRPPRQO XVHG RQO LQ VSHFLDO FODVVHV RI VHUYLFH ,W LV PDGH DV D VROLG IHOWHG
FRYHULQJ IRU D FDEOH
Q33. What materials are commonly used as cushions between cable insulation and metallic armor?
METALLIC PROTECTION
0HWDOOLF SURWHFWLRQ LV RI WZR WSHV VKHDWK RU DUPRU $V ZLWK DOO ZLUHV DQG FDEOHV WKH WSH RI
SURWHFWLRQ QHHGHG ZLOO GHSHQG RQ WKH HQYLURQPHQW ZKHUH WKH ZLUH RU FDEOH ZLOO EH XVHG
Metallic Sheath
DEOHV RU ZLUHV WKDW DUH FRQWLQXDOO VXEMHFWHG WR ZDWHU PXVW EH SURWHFWHG E D ZDWHUWLJKW FRYHU 7KLV
ZDWHUWLJKW FRYHU LV HLWKHU D FRQWLQXRXV PHWDO MDFNHW RU D UXEEHU VKHDWK PROGHG DURXQG WKH FDEOH

)LJXUH LV DQ H[DPSOH RI D OHDGVKHDWKHG MDFNHWHG

FDEOH XVHG LQ SRZHU ZRUN 7KLV FDEOH LV D
VWDQGDUG WKUHHFRQGXFWRU WSH (DFK FRQGXFWRU LV LQVXODWHG DQG WKHQ ZUDSSHG LQ D ODHU RI UXEEHUL]HG
WDSH 7KH FRQGXFWRUV DUH WZLVWHG WRJHWKHU DQG URSH RU ILOOHUV DUH DGGHG WR IRUP D URXQG FRUH 2YHU WKLV LV
ZUDSSHG D VHFRQG ODHU RI WDSH FDOOHG D VHUYLQJ )LQDOO D OHDG VKHDWK LV PROGHG DURXQG WKH FDEOH

Figure 1-16.—Lead-sheathed cable.
/HDGVKHDWKHG FDEOH LV RQH RI WKUHH WSHV FXUUHQWO EHLQJ XVHG DOOR OHDG SXUH OHDG DQG UHLQIRUFHG
OHDG $Q DOOROHDG VKHDWK LV PXFK OLNH D SXUH OHDG VKHDWK EXW LV PDQXIDFWXUHG ZLWK SHUFHQW WLQ 7KLV
DOOR LV PRUH UHVLVWDQW WR JRXJLQJ DQG DEUDVLRQ GXULQJ DQG DIWHU LQVWDOODWLRQ 5HLQIRUFHG OHDG VKHDWK LV
XVHG PDLQO IRU RLOILOOHG FDEOHV ZKHUH KLJK LQWHUQDO SUHVVXUHV FDQ EH H[SHFWHG 5HLQIRUFHG OHDG VKHDWK
FRQVLVWV RI D GRXEOH OHDG VKHDWK $ WKLQ WDSH RI KDUGGUDZQ FRSSHU EURQ]H RU RWKHU HODVWLF PHWDO
SUHIHUDEO QRQPDJQHWLF

LV ZUDSSHG DURXQG WKH LQQHU VKHDWK 7KLV WDSH JLYHV FRQVLGHUDEOH DGGLWLRQDO
VWUHQJWK DQG HODVWLFLW WR WKH VKHDWK EXW PXVW EH SURWHFWHG IURP FRUURVLRQ )RU WKLV UHDVRQ D VHFRQG OHDG
VKHDWK LV DSSOLHG RYHU WKH WDSH
Metallic Armor
0HWDOOLF DUPRU SURYLGHV D WRXJK SURWHFWLYH FRYHULQJ IRU ZLUHV DQG FDEOHV 7KH WSH WKLFNQHVV DQG
NLQG RI PHWDO XVHG WR PDNH WKH DUPRU GHSHQG RQ WKUHH IDFWRUV

WKH
HQYLURQPHQW ZKHUH WKH FRQGXFWRUV DUH WR EH XVHG DQG

WKH DPRXQW RI URXJK WUHDWPHQW WKDW LV H[SHFWHG
)LJXUH VKRZV WKUHH H[DPSOHV RI PHWDOOLF DUPRU FDEOH ZLUH EUDLG VWHHO WDSH DQG ZLUH DUPRU

Figure 1-17.—Metallic armor cable.
WIRE-BRAID ARMOR²:LUHEUDLG DUPRU YLHZ $ RI ILJXUH

DOVR NQRZQ DV EDVNHWZHDYH
DUPRU LV XVHG ZKHQ OLJKW DQG IOH[LEOH SURWHFWLRQ LV QHHGHG :LUH EUDLG LV FRQVWUXFWHG PXFK OLNH ILEURXV

EUDLG 7KH PHWDO LV ZRYHQ GLUHFWO RYHU WKH FDEOH DV WKH RXWHU FRYHULQJ 7KH PHWDO XVHG LQ WKLV EUDLG LV
JDOYDQL]HG VWHHO EURQ]H FRSSHU RU DOXPLQXP :LUHEUDLG DUPRU LV PDLQO IRU VKLSERDUG XVH
STEEL TAPE²$ VHFRQG WSH RI PHWDOOLF DUPRU LV VWHHO WDSH 6WHHO WDSH FRYHULQJ YLHZ % RI ILJXUH

LV ZUDSSHG DURXQG WKH FDEOH DQG WKHQ FRYHUHG ZLWK D VHUYLQJ RI MXWH 7KHUH DUH WZR WSHV RI VWHHO
WDSH DUPRU 7KH ILUVW LV FDOOHG LQWHUORFNLQJ DUPRU ,QWHUORFNLQJ DUPRU LV DSSOLHG E ZUDSSLQJ WKH WDSH
DURXQG WKH FDEOH VR WKDW HDFK WXUQ LV RYHUODSSHG E WKH QH[W DQG LV ORFNHG LQ SODFH 7KH VHFRQG WSH LV IODW
EDQG DUPRU )ODWEDQG DUPRU FRQVLVWV RI WZR ODHUV RI VWHHO WDSH 7KH ILUVW ODHU LV ZUDSSHG DURXQG WKH
FDEOH EXW LV QRW RYHUODSSHG 7KH VHFRQG ODHU LV WKHQ ZUDSSHG DURXQG WKH FDEOH FRYHULQJ WKH DUHD WKDW ZDV
QRW FRYHUHG E WKH ILUVW ODHU
WIRE ARMOR²:LUH DUPRU LV D ODHU RI ZRXQG PHWDO ZLUH ZUDSSHG DURXQG WKH FDEOH :LUH
DUPRU LV XVXDOO PDGH RI JDOYDQL]HG VWHHO DQG FDQ EH XVHG RYHU D OHDG VKHDWK VHH YLHZ RI ILJXUH

,W FDQ EH XVHG ZLWK WKH VKHDWK DV D EXULHG FDEOH ZKHUH PRLVWXUH LV D FRQFHUQ RU ZLWKRXW WKH VKHDWK YLHZ
' RI ILJXUH

ZKHQ XVHG LQ EXLOGLQJV
Q34. What are the two types of metallic protection?
Q35. What are the three types of lead-sheathed cables?
Q36. What are the three examples of metallic armor cable that were discussed?

COAXIAL CABLE
RD[LDO FDEOH ILJXUH

LV GHILQHG DV WZR FRQFHQWULF ZLUHV FOLQGULFDO LQ VKDSH VHSDUDWHG E D
GLHOHFWULF RI VRPH WSH 2QH ZLUH LV WKH FHQWHU FRQGXFWRU DQG WKH RWKHU LV WKH RXWHU FRQGXFWRU 7KHVH
FRQGXFWRUV DUH FRYHUHG E D SURWHFWLYH MDFNHW 7KH SURWHFWLYH MDFNHW LV WKHQ FRYHUHG E DQ RXWHU SURWHFWLYH
DUPRU

Figure 1-18.—Coaxial cable.
RD[LDO FDEOHV DUH XVHG DV WUDQVPLVVLRQ OLQHV DQG DUH FRQVWUXFWHG WR SURYLGH SURWHFWLRQ DJDLQVW
RXWVLGH VLJQDO LQWHUIHUHQFH

SUMMARY
,Q WKLV FKDSWHU RX OHDUQHG WKDW FRQGXFWRUV DUH WKH PHDQV IRU WLQJ WKH YDULRXV FRPSRQHQWV RI DQ
HOHFWULFDO RU HOHFWURQLF VVWHP WRJHWKHU 0DQ IDFWRUV GHWHUPLQH WKH WSH RI FRQGXFWRU WR EH XVHG LQ D
VSHFLILF DSSOLFDWLRQ ,Q RUGHU IRU RX WR FRPSDUH WKH GLIIHUHQW WSHV DQG VL]HV RI FRQGXFWRUV ZH GLVFXVVHG
WKH IROORZLQJ IDFWRUV
Unit Size²7KH XQLW VL]H RI D FRQGXFWRU LV WKH PLOIRRW $ PLOIRRW LV D FLUFXODU FRQGXFWRU IRRW ORQJ
ZLWK D GLDPHWHU RI PLO LQFK RU RQHWKRXVDQGWK RI DQ LQFK

Conductor Sizes²7KH VTXDUH PLO DQG WKH FLUFXODU PLO DUH WKH XQLWV RI PHDVXUH XVHG WR GHWHUPLQH
WKH FURVVVHFWLRQDO DUHD RI HOHFWULFDO FRQGXFWRUV 7KH VTXDUH PLO DV LW UHODWHV WR D VTXDUH FRQGXFWRU LV WKH
FURVVVHFWLRQDO DUHD RI D VTXDUH FRQGXFWRU WKDW KDV D VLGH RI PLO 7KH FLUFXODU PLO LV WKH FURVVVHFWLRQDO
DUHD RI D FLUFXODU FRQGXFWRU KDYLQJ D GLDPHWHU RI PLO 7KH FLUFXODU PLO DUHD 0$

RI D FRQGXFWRU LV
FRPSXWHG E VTXDULQJ WKH GLDPHWHU RI WKH FLUFXODU FRQGXFWRU LV PLOV 7KXV D ZLUH KDYLQJ D GLDPHWHU RI
PLOV LQFK

KDV D 0$ RI RU FLUFXODU PLOV ,I WKH FRQGXFWRU LV VWUDQGHG WKH 0$ IRU D VWUDQG
LV FRPSXWHG DQG WKH 0$ IRU WKH FRQGXFWRU LV FRPSXWHG E PXOWLSOLQJ WKH 0$ RI WKH VWUDQG E WKH
QXPEHU RI VWUDQGV 7KH UHODWLRQVKLS RI WKH VTXDUH PLO WR WKH FLUFXODU PLO LV GHWHUPLQHG E FRPSDULQJ WKH
VTXDUH PLO DUHD RI D FLUFXODU FRQGXFWRU KDYLQJ D GLDPHWHU RI PLO $ πU

WR WKH FLUFXODU PLO DUHD RI WKH
VDPH FRQGXFWRU '

7KHUHIRUH WKHUH LV VTXDUH PLO WR FLUFXODU PLO 7KHUH DUH PRUH FLUFXODU PLOV
WKDQ VTXDUH PLOV LQ D JLYHQ DUHD
Specific Resistance²7KH VSHFLILF UHVLVWDQFH RI D VXEVWDQFH LV WKH UHVLVWDQFH LQ RKPV RIIHUHG E D
XQLW YROXPH WKH FLUFXODUPLOIRRW

WR WKH IORZ RI HOHFWULF FXUUHQW 7KH WKUHH IDFWRUV WKDW DUH XVHG WR
FDOFXODWH WKH VSHFLILF UHVLVWDQFH RI D SDUWLFXODU FRQGXFWRU DUH

WKH VSHFLILF UHVLVWDQFH RI D XQLW YROXPH RI WKH VXEVWDQFH IURP ZKLFK WKH FRQGXFWRU LV PDGH 7KH
VSHFLILF UHVLVWDQFH IRU YDULRXV VL]HV DQG OHQJWKV RI VWDQGDUG VROLG FRSSHU ZLUH FDQ EH GHWHUPLQHG E WKH
XVH RI WDEOHV
Wire Gauge²$ ZLUH JDXJH LV XVHG WR GHWHUPLQH WKH $PHULFDQ 6WDQGDUG :LUH *DXJH VL]H RI
FRQGXFWRUV 7KH PHDVXUHPHQW RI D EDUH FRQGXFWRU LV WDNHQ LQ WKH VORW QRW LQ WKH FLUFXODU DUHD DW WKH
ERWWRP RI WKH VORW

Selection of Wire Size²)RXU IDFWRUV PXVW EH FRQVLGHUHG LQ VHOHFWLQJ WKH SURSHU ZLUH VL]H IRU D
SDUWLFXODU HOHFWULFDO FLUFXLW 7KHVH IDFWRUV DUH

WKH
ORFDWLRQ RI WKH ZLUH LQ WKH FLUFXLW DQG

WKH WSH RI LQVXODWLRQ XVHG 6RPH RI WKH WSHV RI LQVXODWLRQ XVHG

LQ D KLJKWHPSHUDWXUH HQYLURQPHQW DUH )(3 H[WUXGHG SROWHWUDIOXRURHWKOHQH DQG VLOLFRQH UXEEHU 7KH
DPELHQW VXUURXQGLQJ

WHPSHUDWXUH RI D FRQGXFWRU LV DQ LPSRUWDQW SDUW RI WRWDO FRQGXFWRU KHDWLQJ
Copper-versus-Aluminum Conductors²7KH WZR PRVW FRPPRQ PHWDOV XVHG IRU HOHFWULFDO
FRQGXFWRUV DUH FRSSHU DQG DOXPLQXP 6RPH DGYDQWDJHV RI FRSSHU RYHU DOXPLQXP DV D FRQGXFWRU DUH WKDW
FRSSHU KDV KLJKHU FRQGXFWLYLW LV PRUH GXFWLOH KDV D KLJKHU WHQVLOH VWUHQJWK DQG FDQ EH HDVLO VROGHUHG
7ZR DGYDQWDJHV RI DOXPLQXP ZLUH IRU FDUULQJ HOHFWULFLW RYHU ORQJ GLVWDQFHV DUH LWV OLJKWQHVV DQG LW
UHGXFHV FRURQD WKH GLVFKDUJH RI HOHFWULFLW IURP D ZLUH DW KLJK SRWHQWLDO

Temperature Coefficient of Resistance²7KH WHPSHUDWXUH FRHIILFLHQW RI UHVLVWDQFH LV WKH DPRXQW RI
LQFUHDVH LQ WKH UHVLVWDQFH RI D RKP VDPSOH RI D FRQGXFWRU SHU GHJUHH RI WHPSHUDWXUH ULVH DERYH ž
7KH UHVLVWDQFH RI FRSSHU DQG RWKHU SXUH PHWDOV LQFUHDVHV ZLWK DQ LQFUHDVH LQ WHPSHUDWXUH
Conductor Insulation²,QVXODWRUV KDYH D UHVLVWDQFH WKDW LV VR JUHDW WKDW IRU DOO SUDFWLFDO SXUSRVHV
WKH DUH QRQFRQGXFWRUV 7ZR IXQGDPHQWDO SURSHUWLHV RI LQVXODWLQJ PDWHULDOV DUH

WKH UHVLVWDQFH WR FXUUHQW OHDNDJH WKURXJK WKH LQVXODWLRQ 'LHOHFWULF VWUHQJWK LV WKH DELOLW RI WKH
LQVXODWLRQ PDWHULDO WR ZLWKVWDQG SRWHQWLDO GLIIHUHQFH 7KH GLHOHFWULF VWUHQJWK RI DQ LQVXODWRU LV GHWHUPLQHG
E UDLVLQJ WKH YROWDJH RQ D WHVW VDPSOH XQWLO LW EUHDNV GRZQ
Insulating Materials²6RPH FRPPRQ LQVXODWLQJ PDWHULDOV KDYH SURSHUWLHV DQG VDIHW SUHFDXWLRQV
WKDW VKRXOG EH UHPHPEHUHG 7KHVH DUH
• 7KH SXUSRVH RI FRDWLQJ D FRSSHU FRQGXFWRU ZLWK WLQ ZKHQ UXEEHU LQVXODWLRQ LV XVHG LV WR SUHYHQW
WKH LQVXODWLRQ IURP GHWHULRUDWLQJ GXH WR FKHPLFDO DFWLRQ
• :KHQ H[WUXGHG SROWHWUDIOXRURHWKOHQH LQVXODWLRQ LV KHDWHG FDXWLRQ VKRXOG EH REVHUYHG QRW WR
EUHDWKH WKH YDSRUV
• 7KH PRVW FRPPRQO XVHG LQVXODWLQJ PDWHULDOV IRU H[WUHPHO KLJKYROWDJH FRQGXFWRUV DUH
YDUQLVKHG FDPEULF DQG RLOLPSUHJQDWHG SDSHU
• 0DJQHW ZLUH LV WKH FRPPRQ QDPH IRU HQDPHOLQVXODWHG ZLUH XVHG LQ PHWHUV UHODV VPDOO
WUDQVIRUPHUV PRWRU ZLQGLQJV DQG VR IRUWK
• 7KH 1DY LV JHWWLQJ DZD IURP XVLQJ DVEHVWRV LQVXODWLRQ EHFDXVH DVEHVWRV ILEHUV FDQ FDXVH OXQJ
GLVHDVH DQGRU FDQFHU
• $VEHVWRV LQVXODWLRQ EHFRPHV D FRQGXFWRU ZKHQ LW JHWV ZHW

Conductor Protection²7KHUH DUH VHYHUDO WSHV RI FRQGXFWRU SURWHFWLRQ LQ XVH 7KH WSH FRPPRQO
XVHG DERDUG 1DY VKLSV LV ZLUHEUDLG DUPRU

ANSWERS TO QUESTIONS Q1. THROUGH Q36.

A1. To allow comparisons between conductors of different sizes and resistance.
A2. 375 mils (move the decimal three places to the right).
A3. A circular conductor with a diameter of 1 mil and a length of 1 foot.
A4. The cross-sectional area of a square conductor with a side of 1 mil.
A5. The cross-sectional area of a circular conductor with a diameter of 1 mil.
A6. Circular mil area (CMA) = D2 (in mils) × number of strands0.0004 inch = 4 mils (CMA) = 4 2 ×
19 (strands)(CMA) = 16 × 19 = 304 mils.
A7. The resistance of a unit volume of a substance.
A8. Length, cross-sectional area, and specific resistance of a unit volume of the substance from
which the conductor is made.
A9. 1,000 ft = 10.4 ohms1,500 ft = 1.5 × 0.4 = 15.6 ohms
A10. In the parallel walled slot not the circular area.
A11. Conductor size, the material it is made of the location of the wire in a circuit, and the type of
insulation used.
A12. FEP, extruded polytetrafluoroethylene, and silicone rubber.
A13. The heat surrounding the conductor is an important part of total conductor heating.
A14. It is light and reduces corona.
A15. It has higher conductivity, it is more ductile, it has relatively high tensile strength, and it can be
easily soldered.
A16. The amount of increase in the resistance of a 1-ohm sample of the conductor per degree of
temperature rise above 0º C
A17. It increases.
A18. Conductors have a very low resistance and insulators have a resistance that is so great that, for
all practical purposes, they are nonconductors.
A19. Insulation resistance and dielectric strength.
A20. The resistance to current leakage through the insulation.
A21. The ability of the insulation material to withstand potential difference.
A22. By raising the voltage on a test sample until it breaks down.
A23. To prevent the rubber insulation from deteriorating due to chemical action.
A24. Avoid breathing the vapors when the insulation is heated.
A25. Breathing asbestos fibers can cause lung disease and/or cancer
A26. It will become a conductor.
A27. Varnished cambric and oil-impregnated paper.
A28. Magnet wire.

A29. Metallic coat.
A30. Three.
A31. Fibrous Braid.
A32. Rubber-filled cloth tape and a combination of cotton cloth and rubber.
A33. Jute and Asphalt coverings.
A34. Sheath and armor
A35. Alloy lead, pure lead, and reinforced lead.
A36. Wire braid, steel tape, and wire armor

CHAPTER 2

WIRING TECHNIQUES

LEARNING OBJECTIVES

Upon completing this chapter, you should be able to:

1. State the basic requirements for any splice and terminal connection, including the preferred wire-
stripping method.

2. State the reason the ends of the wire are clamped down after a Western Union splice has been
made.

3. Explain the major advantage of the crimped terminal over the soldered terminal.

4. Name the two types of insulation commonly used for noninsulated splices and terminal lugs.

5. State an advantage of using preinsulated terminal lugs and the color code used for each.

6. Explain the procedures for crimping terminal lugs with a hand crimp tool.

7. Recall the physical description and operating procedures for the HT-900B/920B compressed
air/nitrogen heating tool.

8. Recall the safety precautions for using the compressed air/nitrogen heating tool.

9. Recall the procedures, precautions, and tools associated with soldering.

10. Explain the procedures and precautions for tinning wire.

11. Recall the types of soldering irons and their uses.

12. State the purposes and required properties of flux.

13. State the purpose for lacing conductors.

14. Recall when double lacing of wire bundles is required.

15. Recall the requirements for using spot ties.

WIRING TECHNIQUES

This chapter will assist you in learning the basic skills of proper wiring techniques. It explains the
different ways to terminate and splice electrical conductors. It also discusses various soldering techniques
that will assist you in mastering the basic soldering skills. The chapter ends with a discussion of the
procedure to be followed when you lace wire bundles within electrical and electronic equipment.

2-1

CONDUCTOR SPLICES AND TERMINAL CONNECTIONS

Conductor splices and connections are an essential part of any electrical circuit. When conductors
join each other or connect to a load, splices or terminals must be used. Therefore, it is important that they
be properly made. Any electrical circuit is only as good as its weakest link. The basic requirement of any
splice or connection is that it be both mechanically and electrically as sound as the conductor or device
with which it is used. Quality workmanship and materials must be used to ensure lasting electrical
contact, physical strength, and insulation. The most common methods of making splices and connections
in electrical cables is explained in the discussion that follows.

INSULATION REMOVAL

The preferred method of removing insulation is with a wire-stripping tool, if available. A sharp knife
may also be used. Other typical wire strippers in use in the Navy are illustrated in figure 2-1. The hot-
blade, rotary, and bench wire strippers (views A, B, and C, respectively) are usually found in shops where
large wire bundles are made. When using any of these automatic wire strippers, follow the manufacturer's
instructions for adjusting the machine; this avoids nicking, cutting, or otherwise damaging the conductors.
The hand wire strippers are common hand tools found throughout the Navy. The hand wire strippers
(view D of figure 2-1) are the ones you will most likely be using. Wire strippers vary in size according to
wire size and can be ordered for any size needed.

Figure 2-1.—Typical wire-stripping tools.

2-2

Hand Wire Stripper

The procedure for stripping wire with the hand wire stripper is as follows (refer to figure 2-2):

Figure 2-2.—Stripping wire with a hand stripper.

1. Insert the wire into the center of the correct cutting slot for the wire size to be stripped. The wire
sizes are listed on the cutting jaws of the hand wire strippers beneath each slot.

2. After inserting the wire into the proper slot, close the handles together as far as they will go.

3. Slowly release the pressure on the handles so as not to allow the cutting blades to make contact
with the stripped conductor. On some of the newer style hand wire strippers, the cutting jaws
have a safety lock that helps prevent this from happening. Continue to release pressure until the
gripper jaws release the stripped wire, then remove.

Knife Stripping

A sharp knife may be used to strip the insulation from a conductor. The procedure is much the same
as for sharpening a pencil. The knife should be held at approximately a 60º angle to the conductor. Use
extreme care when cutting through the insulation to avoid nicking or cutting the conductor. This
procedure produces a taper on the cut insulation as shown in figure 2-3.

2-3

Figure 2-3.—Knife stripping.

Locally Made Hot-Blade Wire Stripper

If you are required to strip a large number of wires, you can use a locally made hot-blade stripper
(figure 2-4) as follows:

Figure 2-4.—Locally made hot-blade stripper.

1. In the end of a piece of copper strip, cut a sharp-edged V. At the bottom of the V, make a
wire slot of suitable diameter for the size wire to be stripped.

2. Fasten the copper strip around the heating element of an electric soldering iron as shown in
figure 2-4. The iron must be rated at 100 watts or greater in order to transfer enough heat to the
copper strip to melt the wire insulation.

3. Lay the wire or cable to be stripped in the V; a clean channel will be melted in the insulation.

2-4

4. Remove the insulation with a slight pull.

General Wire-Stripping Instructions

When stripping wire with any of the tools mentioned, observe the following precautions:

1. Do not attempt to use a hot-blade stripper on wiring with glass braid or asbestos insulation.
These insulators are highly heat resistant.

2. When using the hot-blade stripper, make sure the blades are clean. Clean the blades with a brass
wire brush as necessary.

3. Make sure all stripping blades are sharp and free from nicks, dents, and so forth.

4. When using any type of wire stripper, hold the wire perpendicular to the cutting blades.

5. Make sure the insulation is clean-cut with no frayed or ragged edges; trim if necessary.

6. Make sure all insulation is removed from the stripped area. Some types of wire are supplied with
a transparent layer between the conductor and the primary insulation. If this is present, remove it.

7. When the hand strippers are used to remove lengths of insulation longer than 3/4 inch, the
stripping procedure must be done in two or more operations. The strippers will only strip about
3/4 inch at one time.

8. Retwist strands by hand, if necessary, to restore the natural lay and tightness of the strands.

9. Strip aluminum wires with a knife as described earlier. Aluminum wire should be stripped very
carefully. Care should be taken not to nick the aluminum wire as the strands break very easily
when nicked.

Q1. What are the basic requirements for any splice or terminal connection?

Q2. What is the preferred method for stripping wire?

Q3. What stripping tool would NOT be used to strip glass braid insulation?

Q4. What tool should be used to strip aluminum wire?

TYPES OF SPLICES

There are six commonly used types of splices. Each has advantages and disadvantages for use. Each
splice will be discussed in the following section.

Western Union Splice

The Western Union splice joins small, solid conductors. Figure 2-5 shows the steps in making a
Western Union splice.

2-5

Neets v04-conductors

Recomendados

Recomendados

Más contenido relacionado

Similar a Neets v04-conductors

Similar a Neets v04-conductors (20)

Más de Sarah Krystelle

Más de Sarah Krystelle (20)

Último

Último (20)

Neets v04-conductors