Electrical Systems - General Requirements, 13
Electrical Calculations, 37
Branch Circuits and Feeders, 59
Chapter 4, Electric Services, 89
Distribution Equipment, 117
Overcurrent Protection, 137
Chapter 7, Utilization Equipment, 163
Chapter 8, Measuring and Testing, 183
Chapter 9, Electric Motors and Motor Controls, 203
Chapter 10, Special Occupancies, 223
Miscellaneous Applications 245
Transformers and Capacitors 257
Chapter 13, Electrical Drawings, 269
Final Examination, 289
Using the Interactive Study Center CD, 340
State Contractor's Examination Offices, 342
Answers to Final Exam Questions, 345
Introduction -- How to Use This Book Take the exam seriously
If you have been installing electrical systems for some time as an apprentice,
helper, or unlicensed electrician, this book is for you. The information between
the covers of this book will cover every subject that is likely to appear on
most electrician's exams - either state or local.
If you are just starting your career as an apprentice electrician, this book is
also for you. It begins at the beginning. You will have no trouble understanding
what is explained here. Read each page carefully and you will soon earn the
recognition that licensed professionals are entitled to in our present society.
The financial rewards are another factor which will make your efforts
In most communities, any electrician working without supervision must be
licensed. For larger electrical construction projects, many states now require
the certification of journeyman electricians as well as specialty electricians,
such as splicers of high-voltage cable. This trend is certain to continue as
legislatures recognize the need to protect the public from incompetents. The
state of Virginia, for example, is now requiring all persons doing electrical
work to be licensed.
Most licensing authorities prepare demanding exams that are a good test of the
examinee's know ledge. These exams help to guarantee that electrical systems
installed in building construction will meet minimum standards for protecting
the lives and health of building occupants (and the buildings themselves) for
many years to come. This also helps to keep insurance rates to a minimum.
Begin your study for any electrician's exam with two points in mind:
Every minute spent studying this book increases your chances of passing the
You can pass any electrician's exam, but only if you study carefully each of the
questions in this book. What you learn from studying is the foundation on which
your professional career will be built.
Understand also that the licensing authority isn't the enemy. They aren't trying
to keep you out of the electrical business. They only want to set some basic
standards and be assured that your installations will be done in a workmanlike
manner and in accordance with the latest edition of the National Electrical
®). The public should be assured that all licensed electricians are
knowledgeable professionals. That's good for society in general, and it's good
for all professional electricians and electrical contractors who live and work
in your area.
Unfortunately, there are too many applicants who are not well prepared when they
sit down to take the electrician's exam. Taking an electrician's exam without
doing a good job of preparation is a complete waste of time - both yours and
that of the licensing authority. The results are predictable. Don't make that
The most common reason for failure is that the applicant didn't study properly
because he didn't know how, or studied the wrong material. This book should put
an end to that excuse. You have in your hands the most complete, easiest-to-use,
most practical reference available for preparing to take the tests that are
actually given today. Read this book carefully, examine every question,
understand all the answers. Do this, and there's no way you will be unprepared
on examination day. You are almost certain to score high.
All the common questions and answers are here, but just knowing the answer is
not always enough. Sometimes it is just as important to understand why
particular answer is correct. That's why
many answers include a quotation or reference section from the National
. Sometimes you will find notes or clarifications under the
answer when there is an important point you might miss.
The National Electrical Code
is used in practically every area of the United
States for inspecting electrical systems in building construction. Most of the
questions appearing on electrician's exams will come directly from Articles and
Sections of the latest NEC
. Therefore a brief review of the individual NEC
sections that apply to electrical systems is in order. Sample questions
concerning all sections of the NEC
may be found in the chapters to follow.
This book, however, is not a substitute for the NEC
. You need a copy of the most
recent edition and it should be kept handy at all times. The more you know about
the code, the more you are likely to refer to it.
There are two basic types of rules in the NEC
: mandatory rules and advisory
rules. Here is how to . recognize the two types of rules and how they relate to
all types of electrical systems.
: All mandatory rules have the terms shall or shall not
The terms mean must
. If a rule is mandatory, you must comply with it.
: All advisory rules have the terms shall be permitted
not be required
in them. The terms in this case mean recommended but not
. If a rule is advisory, compliance is discretionary. If
you want to comply with it, do so. But you don't have to if you don't want to.
Be alert to local amendments to the NEC
. Local ordinances may amend the language
of the NEC, changing it from should to shall
. This means that you must do in
that county or city what may only be recommended in some other area. The office
that issues building permits will either sell you a copy of the code that's
enforced in that county or tell you where the code is sold.
Learning the Layout of the NEC
Begin your study of the NEC
with Articles 100 and 110. These two articles have
the basic information that will make the rest of the NEC easier to understand.
Article 100 defines terms you will need to understand when you apply the code.
Article 110 gives the general requirements for electrical installations. Read
these two articles over several times until you are thoroughly familiar with
all the information they contain. It's time well spent.
Once you're familiar with Articles 100 and 110, you can move on to the rest of
the code. There are several key sections you will use often in servicing
electrical systems. Let's discuss each of these important sections.
Wiring and Protection
Chapter 2 of the NEC
discusses wiring design and protection, the information
electrical technicians need most often. It covers the use and identification
of grounded conductors, branch circuits, feeders, calculations, services,
overcurrent protection, grounding and surge protection. This is essential information for
type of electrical system, regardless of the type.
Chapter 2 is also a "how-to" chapter. It explains how to provide proper spacing
for conductor supports and how to size the proper grounding conductor or
electrode. If you run into a problem related to the design or installation of a
conventional electrical system, you can probably find a solution for it in this
Wiring Methods and Materials
Chapter 3 has the rules on wiring methods and materials. The materials and
procedures to use on a particular system depend on the type of building
construction, the type of occupancy, the location of the wiring in the building,
the type of atmosphere in the building or in the area surrounding the building,
mechanical factors and the relative costs of different wiring methods.
The provisions of this chapter apply to all wiring installations except remote
control switching (Article 725), low-energy power circuits (Article 725),
signal systems (Article 725), communication systems and conductors (Article
800) when these items form an integral part of equipment such as motors and
There are three basic wiring methods used in most modern electrical systems.
Nearly all wiring methods are a variation of one of these three basic methods:
Sheathed cables of two or more conductors, such as NM cable and AC armored
cable (Articles 320 through 340)
Raceway wiring systems, such as rigid and EMT conduit (Articles 342 through
Busways (Article 368)
Article 310 in Chapter 3 gives a complete description of all types of electrical
conductors. Electrical conductors come in a wide range of Sizes and forms. Be
sure to check the working drawings and specifications to see what sizes and
types of conductors are required for a specific job. If conductor type and size
are not specified,
choose the most appropriate type and size meeting standard NEC
Articles 312 through 392 give rules for raceways, boxes, cabinets and raceway
fittings. Outlet boxes vary in size and shape, depending on their use, the size
of the raceway, the number of conductors entering the box, the type of building
construction, and the atmospheric condition of the areas. Chapter 3 should
answer most questions on the selection and use of these items.
does not describe in detail all types and sizes of outlet boxes. But
manufacturers of outlet boxes have excellent catalogs showing all of their
products. Collect these catalogs. They're essential to your work.
Equipment for General Use
Chapter 4 of the NEC
begins with the use and installation of flexible cords and
cables, including the trade name, type, letter, wire size, number of conductors,
conductor insulation, outer covering and use of each. The chapter also includes
fixture wires, again giving the trade name, type, letter and other important
Article 404 covers the switches you will use to control electrical circuits.
Article 406 covers receptacles and convenience outlets used to connect portable
equipment to electric circuits. Get the manufacturers' catalogs on these items.
They will provide you with detailed descriptions of each of the wiring devices.
Article 408 covers switchboards and panelboards, including their location,
installation methods, clearances, grounding and overcurrent protection.
Article 410 on lighting fixtures is especially important. It gives installation
procedures for fixtures in specific locations. For example, it covers fixtures
near combustible material and fixtures in closets. The NEC does not describe the
number of fixtures needed in a given area to provide a certain amount of
Article 430 covers electric motors, including mounting the motor and making
electrical connections to it.
Electrician's Exam Preparation Guide
Articles 440 through 460 cover air conditioning and heating equipment,
transformers and capacitors.
Article 480 gives most requirements related to battery-operated electrical
systems. Storage batteries are seldom thought of as part of a conventional
electrical system, but they often provide standby emergency lighting service.
They may also supply power to security systems that are separate from the main
AC electrical system.
Chapter 5 of the NEC
covers special occupancy areas. These are areas where the
sparks generated by electrical equipment may cause an explosion or fire. The
hazard may be due to the atmosphere of the area or just the presence of a
volatile material in the area. Commercial garages, aircraft hangers and service
stations are typical special occupancy locations.
Articles 500 through 503 cover the different types of special occupancy
atmospheres where an explosion is possible. The atmospheric groups were
established to make it easy to test and approve equipment for various types of
Section 501 covers the installation of explosion proof wiring. An
explosion-proof system is designed to prevent the ignition of a surrounding
explosive atmosphere when arcing occurs within the electrical system.
There are three classes of special occupancy locations:
Class I (Article 501): Areas containing flammable gases or vapors in the air.
Class I areas include paint spray booths, dyeing plants where hazardous liquids
are used, and gas generator rooms.
Class II (Article 502): Areas where combustible dust is present, such as
grain handling and storage plants, dust and stock collector areas and
sugar-pulverizing plants. These are areas where, under normal operating
conditions, there may be enough combustible dust in the air to produce explosive
or ignitable mixtures.
Class III (Article 503): Areas that are hazardous because of the presence of
easily ignitable fibers or flyings in the air, although not in large enough
quantity to product ignitable mixtures. Class III locations include cotton
mills, rayon mills and clothing manufacturing plants.
Articles 511 and 514 regulate garages and similar locations where volatile or
flammable liquids are used. While these areas are not always considered
critically hazardous locations, there may be enough danger to require special
precautions in the electrical installation. In these areas, the NEC requires
that volatile gases be confined to an area not more than 18 inches above the
floor. So in most cases, conventional raceway systems are permitted above this
level. If the area is judged critically hazardous, explosion-proof wiring
(including seal-offs) may be required.
Article 520 regulates theaters and similar occupancies where fire and panic can
cause hazards to life and property. Drive-in theaters do not present the same
hazards as enclosed auditoriums. But the projection rooms and adjacent areas
must be properly ventilated and wired for the protection of operating personnel
and others using the area.
Chapter 5 also covers residential storage garages, aircraft hangars,
agricultural buildings, service stations, bulk storage plants, health care
facilities, marinas and boat yards, mobile homes and parks, and recreation
vehicles and parks.
Article 600 covers electric signs and outline lighting. Article 610 applies to
cranes and hoists. Article 620 covers the majority of the electrical work
involved in the installation and operation of elevators, dumbwaiters, escalators
and moving walks. The manufacturer is responsible for most of this work. The
electrician usually just furnishes a feeder terminating in a means of disconnect
in the bottom of the elevator shaft. The electrician may also be responsible for
a lighting circuit to a junction box midway in the elevator shaft for
connecting the elevator cage lighting cable and exhaust
fans. Articles in Chapter 6 of the NEC give most of the requirements for these
Article 630 regulates electric welding equipment. It is normally treated as a
piece of industrial power equipment requiring a special power outlet. But there
are special conditions that apply to the circuits supplying welding equipment.
These are outlined in detail in Chapter 6 of the NEC.
Article 640 covers wiring for sound-recording and similar equipment. This type
of equipment normally requires low-voltage wiring. Special outlet boxes or
cabinets are usually provided with the equipment. But some items may be mounted
in or on standard outlet boxes. Some sound-recording electrical systems require
direct current, supplies from rectifying equipment, batteries or motor
generators. Low-voltage alternating current comes from relatively small
transformers connected on the primary side to a 120-volt circuit within the
Other items covered in Chapter 6 of the NEC include: X-ray equipment (Article
660), induction and dielectric heat-generating equipment (Article 665) and
machine tools (Article 670).
If you ever have work that involves Chapter 6, study the chapter before work
begins. That can save a lot of installation time. Here is another way to cut
down on labor hours and prevent installation errors. Get a set of rough-in
drawings of the equipment being installed. It is easy to install the wrong
outlet box or to install the right box in the wrong place. Having a set of
rough-in drawings can prevent those simple but costly errors.
In most commercial buildings, the NEC and local ordinances require a means of
lighting public rooms, halls, stairways and entrances. There must be enough
light to allow the occupants to exit from ~e building if the general building
lighting is interrupted. Exit doors must be clearly indicated by illuminated exit
Chapter 7 of the NEC covers the installation of emergency lighting systems.
These circuits should be arranged so that they can automatically transfer to an
alternate source of current, usually storage
batteries or gasoline-drive generators. As an alternative, you can connect them
to the supply side of the main service so disconnecting the main service switch
would not disconnect the emergency circuits. See Article 700.
How to Prepare for the Exam
This book is a guide to preparing for the journeyman or master electrician's
exam. It isn't a substitute for studying the recommended references and it
won't teach you the electrical trade. But it will give you a complete knowledge
of the type of questions asked in the electrician's exam. It will also give you
a "feel" for the examination and provide some of the confidence you need to
Emphasis is on multiple-choice questions because that's the style that nearly
all tests utilize. Questions are grouped into chapters. Each chapter covers a
single subject. This will help you discover your strengths and weaknesses. Then
when you take the two "final" sample exams in the back of this book, analyze the
questions you miss. You'll probably notice you are weaker in some subjects than
others. When these areas have been discovered, you will know that further study
is necessary in these areas.
In answering questions on the NEC, remember this point: All exam questions are
based on minimum NEC requirements. If the minimum wire size permitted under the
NEC to carry 20 amperes is No. 12 AWG and you answer No. 10 AWG (minimum size
for 30 amperes) just to play it safe, your answer is incorrect.
The preparatory questions in the front part of this book have the answer after
each question. When reading a question, cover the answer. Read the question
carefully. Mark your answer on a separate sheet of paper before looking at the
correct answer. Check to see if your answer is correct. If it isn't, read the
code responses to find out why it is wrong.
How to Study
Set aside a definite time to study, following a schedule that meets your needs.
Studying a couple of hours two or three nights each week is better
than studying all day on, say, Saturdays. The average mind can only concentrate
for approximately four hours without taking a break. There's no point in
studying if you don't retain much of the information. Study alone most of the
time, but spend a few hours reviewing with another electrician buddy before exam
day. You can help each other dig out the facts and concepts you will need to
pass the exam.
Try to study in a quiet, well-lighted room that is respected as your study space
by family members and friends. If it's hard to find a spot like that in your
home, go to the local library where others are reading and studying.
Before you begin to study, spend a few minutes getting into the right frame of
mind. That's important. You don't have to be a genius to pass the
electrician's exam. But good motivation will nearly guarantee your success. No
one can provide that motivation but you. Getting your license is a goal you set
for yourself; it's your key to the future a satisfying career in the electrical
As you study the NEC and other references, highlight important points with a
marker. This makes it easier to find important passages when you're doing the
final review - and when you're taking the exam.
Put paper tabs on the corners of each major section in all the references you
will take into the exam room. On the portion of the tab that extends beyond the
edge of the book, write the name of the section or the subject. That makes
locating each section easier and quicker - an important consideration on an
open book test. Speed in locating answers is important. In the sample exams at
the end of this book, which are based on actual state and county examinations,
you will have from two to four minutes to answer each question, so you don't
have time to daydream or mess around. If you want to pass the exam, you must
take it seriously.
Your study plan should allow enough time to review each reference at least three
times. Read carefully the first time. The next review should take only about 10%
of the time that the first reading took. Make a final review of all references
and notes on the day before the exam. This is the key to
success in passing the exam: Review, review, review! The more you review, the
better your grasp of the information and the faster you will be able to find the
Questions on state and local examinations are usually compiled by members of the
electrician's examination board. Board members usually include several
electrical contractors, a registered electrical engineer, electrical
inspectors, and perhaps a trade school instructor. Most electrician's exams will
include questions on the NEC, general knowledge of electrical practice,
theoretical questions, and local ordinance rules. All of these fields are
covered in this preparation guide. Questions about the NEC, including rules and
design calculations, comprise from 70% to 80% of the examination.
State examinations are usually given twice a year, or perhaps every three
months. County and local exams may be taken almost any time with prior notice to
the local inspectors. Most have several basic exams that are used in rotation.
But the same examination will never be administered twice in a row.
The people compiling the exams maintain a bank of several hundred questions
covering each test subject. Questions are selected at random, and chances are
that some of the questions on any exam have already been used on an earlier
examination. Many of the questions appearing on actual electrician's exams will
closely resemble questions appearing in this book.
The format of the actual examination, the time allowed, and the reference
material which the applicant may be allowed to take into the examination room
vary with each locality. Typically, an applicant is allowed six to eight hours
to complete the examination. Applicants are usually required to report to the
examination room at 8 a.m. where the proctors take about 15 minutes to explain
the rules of taking the exam. The applicants then work on the "morning" exam
until noon. After an hour break for lunch, the "afternoon" exam begins at 1 p.m.
and applicants are given until about 4 p.m. to complete this portion.
The Answer Sheet
Most answer sheets used today are designed for computer grading. Each question
on the exam is numbered. Usually there will be four or five possible responses
for each question. You will be required to mark the best answer on the answer
sheet. The following is a sample of a multiple choice question:
1) Richmond is the capitol city of what state?
(A) Florida (C) Virginia
(B) Maryland (D) California
You should mark answer C for question 1 on the answer sheet.
Answer sheets will vary slightly for each examining agency so be sure to follow
any instructions on that sheet. Putting the right answers on the wrong section
will almost certainly cause you to fail.
The Night Before
Give your mind a rest! If you have not prepared correctly for the exam by this
time, then you can't cram it all into your brain in one night. So take it easy.
If the place of the examination is more than an hour's drive from your home, you
might want to stay at a motel in the city where the examination is being held.
Getting up at, say, 4 a.m. and driving a couple of hours in heavy traffic will
not help you to pass the exam. On the other hand, a drive to the location the
afternoon before the exam, a good dinner and a relaxing evening watching TV will
increase your possibilities of passing. Just don't stay up too late.
Be sure to have all of your reference material with you and get a good night's
sleep before the day of the exam. If you have prepared yourself correctly, you
should pass with flying colors.
On the day of your examination, listen carefully to any oral instructions given
and read the printed
directions. Failing to follow instructions will probably disqualify you.
You will seldom find any trick questions, but many will require careful reading.
Certain words (like shall, should, always and never) can make a big difference
in your answer.
Sometimes several of the answers may seem possible, but only one will be
correct. If you are not sure of the answer, use the process of elimination.
There are several ways to take an exam, but the following is the method I used
to pass the Virginia State Electrical Contractor's Exam a few years ago. This
method is merely a suggestion: if another way suits you best, by all means use
When the exam booklets were passed out and the applicants were given permission
to open them, I spent the first few minutes going over the exam booklet, noting
the number of questions. This allowed me to pace myself. I noted there were 100
questions on the morning exam - which gave me less than three minutes to spend
on each one.
I then started with question No.1. When I found one that I wasn't sure of, I
merely skipped over this until I came to one that I definitely knew the answer.
This way I had gone through the entire test booklet once and had answered about
50% of the questions in a little over one hour. I was quite sure that I had
answered all of these questions correctly. However, 70% is usually the minimum
passing grade and at this point, I had only 50% of the questions answered. But
I still had about three hours to spend on the tougher questions.
I then started back at the beginning of the exam and went down the list of
questions until I found one that was unanswered. This process continued until I
had answered all questions to the best of my ability. I spent the remaining time
reviewing my previous answers, making changes as necessary.
After lunch, the "afternoon" portion of the exam was handed out, and I used the
same procedure as before. I found out a few days later that I had scored 94% on
If you're getting ready to take the electrician's exam and drowning in
pages of tables, rules and exceptions, here's the book you need. Electrical Systems
You'll find almost a thousand multiple-choice questions to study, based on
actual tests administered over the last few years in states and counties across
the U.S. The questions are written just as they are on the exams, except the
answer and an explanation is provided below each question. You can test your
knowledge as you go through the book.
Each chapter of the book begins with a basic explanation of the topic, followed
by dozens of questions on that particular area of electrical work. There are
diagrams to aid you in understanding the subject, and direct references to the
latest National Electrical Code® sections or tables that apply to the questions.
The chapters cover practically all the subjects likely to be tested on the exam,
Electrical Measuring and Testing
Branch Circuits and Feeders
Electrical Motors and Motor Controls
Transformers and Capacitors
Read each question and try to pick the correct answer. Then look to see if you
were right. If not, review the NEC
® section cited and make sure you understand
why the given answer is correct.
Once you've been through the book and can answer all the questions, it's time to
take the practice test included in the back. Take the test as though it were the
real one. Give yourself the allotted time. Then grade yourself. The answer page
is just before the index. Any questions you missed - go back to the chapter on
that subject and review it again.
A CD-ROM with all the questions in the book, in an interactive format with
the answers and any pertinent code sections popping up with a mouse click. Let
your computer be your teacher and make studying for the exam fun. You can even
take the practice test on your computer, and let it grade you. This new way to
study is far easier than forcing yourself to stare at a book for hours on end.
Haven't applied for the exam yet? There's a listing of State Contractor's
Examination Offices and who to contact for an application form. You'll also
learn how to prepare for the exam and what to expect on examination day. This is
a tool that every journeyman and master electrician candidate will find well
worth their investment.
held a master electrician's license in Virginia and practiced the
trade for many years. Becoming an expert in NEC
® requirements for all types of
electrical installations, he turned to publishing his knowledge in scores of
and other technical manuals, trade journals and technical magazines.
is a licensed master electrician in Florida. He's maintained and
installed the full range of electrical systems, up to giant commercial and
industrial projects, including fiber optic networks, highway lighting,
signalization and toll collection projects. An electrical inspector, consultant,
and author of several technical manuals, he is uniquely qualified to keep the
questions in this manual correct and in compliance with the latest NEC