Audel Questions and Answers for Electrician's Examinations E-Book

Paul Rosenberg

• Herausgeber: John Wiley & Sons
• Kategorie: Lebensstil
• Serie: Audel Technical Trades Series
• Sprache: Englisch
• Veröffentlichungsjahr: 2011

Seitenzahl: 318

Beschreibung

An essential resource for passing electrician's examinations To pass your state and local licensing exams, you need knowledge and confidence. This comprehensive review guide gives you plenty of both. It's packed with sample questions to help you focus your efforts, review material on all aspects of the 2011 National Electrical Code (NEC), the lowdown on business competency requirements, and tips for studying and test-taking that will help you conquer anxiety ahead. * Learn the definitions, specifications, and regulations of the 2011 NEC * Acquire test-taking skills with examples of questions and answers that are similar to the ones on the license tests * Brush up on taxes, unemployment, workers compensation, OSHA, lien laws, and other aspects of the business competency exam * Boost your confidence with studying and test-taking tips A reliable and trusted resource for many decades, this newest edition delivers all of the vital content electricians need to made the grade and advance their careers.

Leseprobe

Contents

Title Page

Copyright

Introduction

1: Review Definitions

2: Ohm’s Law and Other Electrical Formulas

Series Circuits

Parallel Circuits

Units of Area and Resistance

Skin Effect

Voltage-Drop Calculations

Formulas for Determining Alternating Current in Alternating-Current Circuits

Formulas for Combining Resistance and Reactance

Relative Conductivity

3: Power and Power Factor

4: Lighting

5: Branch Circuits and Feeders

6: Transformer Principles and Connections

7: Wiring Design and Protection

8: Wiring Methods and Materials

9: Batteries and Rectification

10: Voltage Generation

11: Equipment for General Use

12: Motors

13: Motor Controls

14: Special Occupancies and Hazardous (Classified) Locations

15: Grounding and Ground Testing

Answers to Questions 15-46 to 15-74

16: Data and Communications Wiring

17: Business Competency Exams

Appendix A: Necessary Mathematics

Transposing Formulas

The Pythagorean Theorem

Fractions

Decimals

Geometric Functions

Index

This book is printed on acid-free paper.

Copyright © 2011 by John Wiley & Sons, Inc. All rights reserved

Published by John Wiley & Sons, Inc., Hoboken, New Jersey

Published simultaneously in Canada

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Library of Congress Cataloging-in-Publication Data:Rosenberg, Paul. Audel questions and answers for electrician’s examinations / Paul Rosenberg. – All new 15th ed. p. cm. – (Audel technical trades series ; 45) Includes index. ISBN 978-1-118-00388-6 (pbk.); ISBN 978-1-118-02615-1 (ebk); ISBN 978-1-118-02616-8 (ebk); ISBN 978-1-118-02617-5 (ebk); ISBN 978-1-118-02618-2 (ebk); ISBN 978-1-118-02619-9 (ebk) 1. Electrical engineering–Examinations, questions, etc. 2. Electricians–Licenses–United States. 3. National Fire Protection Association. National Electrical Code (2002) I. Title. TK169.R67 2011 621.319′24076–dc22 2010053403

Introduction

Tips on Taking Tests

It is the author’s experience that, for most electricians, knowing how to take a test is almost as important as knowing the technical information, as far as obtaining a passing grade is concerned. A great number of electricians fear tests more than they fear 480 volts.

Really, there is no good reason why this should be so. After all, if hundreds of thousands of men and women can pass these tests, anyone interested who gives a real effort and pays particular attention to some basic rules can succeed. Some basic rules for taking tests are these:

1. Know the material being covered.

2. Know the format of the test.

3. Be physically and mentally prepared on the exam day.

4. RELAX!

5. Work the test in the smartest way you can.

The first point, knowing the material being covered, is a mandatory prerequisite. Most test failures come from violating this rule. No, it isn’t always easy to learn all the material to be tested. It requires hours—sometimes many hours—of studying, when you’d rather be doing other things. It means that you have to make your brain work harder than it wants to, going over the material again and again. Sorry, but unless you have an exceptional aptitude for learning there are no shortcuts for hard, intense study. A good study guide (like this book) is about as much help as you can get.

The second rule for taking tests is that you need to know the format of the test. Some of the things you need to know are the following:

How many questions are on the test?

How many questions are open-book?

How many are closed-book?

Do all questions count for the same number of points?

Is there a penalty for wrong answers?

How much time is allowed for each section of the test?

Who wrote the test?

How will the test be graded?

By knowing the answers to these questions, you can plan your efforts intelligently. For example, if certain questions will count for more points than others, you should be ready to spend more time and effort on those questions. By knowing the time limits, you can calculate how much time you have for each question, and so on. Get answers to all of these questions and consider all of these facts as you prepare for the exam.

Now, as for being physically and mentally prepared: I think most readers are familiar with the way athletes prepare for an event. They make sure they eat the right kinds of food, so that they have enough energy. They get plenty of sleep, and they come to the event planning to win. The same thing should be done in preparation for a test.

The most important factor is what we already mentioned: planning to win. Psychologists have found that the results one achieves are directly related to what one expects to receive. If you believe that you will do well, you are quite likely to do well. (Of course, you can kill the whole deal by not studying, then faking your belief in yourself.) If you expect to do poorly, you probably will, regardless of how much studying you’ve done.

Remember, it does not matter what you wish for; what matters is what you expect. I’ll pass on to you one of my favorite quotes along these lines, from Robert J. Ringer: “The results you produce in life are inversely proportional to the degree to which you are intimidated.”

If you want to improve your confidence (expectations) in your test-taking abilities, picture yourself as having aced the test; refuse to imagine yourself failing. You’ll also have to spend as much time studying as is necessary to believe in yourself.

On the day of a test, you want to walk in well rested (but not still groggy), having been well fed (but not full), and with a subdued confidence. Generally, heavy studying the night before the test is not a good idea. Do a light review and leisurely go over difficult parts of the information if you like, but the night before is not the time to get intense. You should have been intense two weeks ago. The night before the test is a time to eat well and go to bed early. Try not to eat within two or three hours of the test, as it tends to bog you down. It has been said that the level of mental efficiency is greatest on an empty stomach.

Confidence is built on a good knowledge of the material to be covered and the ability to pass with style.

Once you enter the test location, relaxing is very important. If you choke up during the test, you are automatically taking 5 points off of your score, and possibly more. You should have the same attitude as runners who show up for races they know they will win. They are ready to run their fastest, but they are not nervous, because they know that their fastest is good enough.

Before taking the test, clear your mind; don’t get involved in trivial conversations. Then, when it is time to answer the questions, dig into the test with your full strength.

During the test, answer all of the easy questions first. Do all of the questions that you know the answers to; pass up the hard questions for now, and do the ones you know for sure. Then, once you have answered these questions, don’t go over them again; just move on to the next group of questions. Next, do the questions that require some work, but do not do the most difficult questions; save them for last. It is silly to waste half your time on one difficult question. Do the 47 easier questions, and then come back to the 3 especially difficult ones.

Work the test in the smartest possible way. Pay attention to time requirements, books allowed during open-book tests, and so on. For your electrical exam, you should definitely put tabs on your codebook. Bring an electronic calculator with you and some scratch paper (as long as you are allowed to). Rather than buying a set of codebook tabs, I recommend that you create your own. Tab the index and the sections of the code that you use most frequently. I generally put tabs on the following:

Tables 250.66 and 250.122 (sizes of ground wires)

Table 310.15(B) (wire ampacities)

Appendix C (conduit fill tables)

Article 230 (services)

Table 300.5 (burial depths)

Tables 370.6 (number of wires in boxes)

Article 430 (motors)

Article 450 (transformers)

Article 490 (over 600 volts)

Article 500 (hazardous location wiring)

Article 590 (temporary installations)

Article 700 (emergency systems)

Remember: If hundreds of thousands of other people have passed these tests, you can, too — if you prepare.

Electrical Symbols

To avoid confusion, American Standards Association (ASA) policy requires that the same symbol not be included in more than one standard. If the same symbol were to be used in two or more standards and one of these standards was revised, changing the meaning of the symbol, considerable confusion could arise over which symbol was correct, the revised or the unrevised.

The symbols in this category include, but are not limited to, those in the following list. The reference numbers are the American Standard Y32.2 item numbers.

List of Symbols

1.0 Lighting Outlets

*In the case of combination continuous-row fluorescent and incandescent spotlights, use combinations of the above Standard symbols.

**In the case of a continuous-row bare-lamp fluorescent strip above an area-wide diffusion means, show each fixture run, using the Standard symbol; indicate area of diffusing means and type of light shading and/or drawing notation.

2.0 Receptacle Outlets

Unless noted to the contrary, it should be assumed that every receptacle will be grounded and will have a separate grounding contact.

Use the uppercase subscript letters described under Section 2 item a-2 of this Standard when weatherproof, explosion-proof, or some other specific type of device will be required.

*Use numeral or letter, either within the symbol or as a subscript alongside the symbol keyed to explanation in the drawing list of symbols, to indicate type of receptacle or usage.

*Use numeral or letter, either within the symbol or as a subscript alongside the symbol keyed to explanation in the drawing list of symbols, to indicate type of receptacle or usage.

3.0 Switch Outlets

Signaling System Outlets

4.0 Institutional, Commercial, and Industrial Occupancies

These symbols are recommended by the American Standards Association but are notused universally. The reader should remember not to assume that these symbols will be used on any certain plan and should always check the symbol list on the plans to verify whether these symbols are actually used.

Signaling System Outlets

5.0 Residential Occupancies

When a descriptive symbol list is not employed, use the following signaling system symbols to identify standardized, residential-type, signal-system items on residential drawings. Use the basic symbols with a descriptive symbol list when other signal-system items are to be identified.

6.0 Panelboards, Switchboards, and Related Equipment

7.0 Bus Ducts and Wireways

*Identify by notation or schedule.

8.0 Remote Control Stations for Motors or Other Equipment*

*Identify by notation or schedule.

9.0 Circuiting

Wiring method identification by notation on drawing or in specification.

10.0 Electric Distribution or Lighting System, Underground

*Identify by notation or schedule.

11.0 Electric Distribution or Lighting System, Aerial

*Identify by notation or schedule.

4 Arrester, Lighting Arrester (Electric surge, etc.) Gap

7 Battery

11 Circuit Breakers

Note 11.3A—On a power diagram, the symbol may be used without other identification. On a composite drawing where confusion with the general circuit element symbol (item 12) may result, add the identifying letters CB inside or adjacent to the square.

13 Circuit Return

15 Coil, Magnetic Blowout*

*The broken line (— - —) indicates where line connection to a symbol is made and is not a part of the symbol.

23 Contact, Electrical

For buildups or forms using electrical contacts, see applications under CONNECTOR (item 19), RELAY (item 66), and SWITCH (item 76). See DRAFTING PRACTICES (item 0.4.6).

It is standard procedure to show a contact by a symbol that indicates the circuit condition produced when the actuating device is in the nonoperated, or deenergized, position. It may be necessary to add a clarifying note explaining the proper point at which the contact functions—the point where the actuating device (mechanical, electrical, etc.) opens or closes due to changes in pressure, level, flow, voltage, current, etc. When it is necessary to show contacts in the operated, or energized, condition—and where confusion would otherwise result—a clarifying note shall be added to the drawing. Contacts for circuit breakers, auxiliary switches, etc., may be designated as shown below:

a. Closed when device is in energized or operated position.

b. Closed when device is in deenergized or nonoperated position.

aa. Closed when operating mechanism of main device is in energized or operated position.

bb. Closed when operating mechanism of main device is in deenergized or nonoperated position.

[See American Standard C37.2-1962 for details.]

In the parallel-line contact, symbols showing the length of the parallel lines shall be approximately 1¼times the width of the gap (except for item 23.6).

24 Contactor

See also RELAY (item 66).

Contactor symbols are derived from fundamental contact, coil, and mechanical connection symbols and should be employed to show contactors on complete diagrams. A complete diagram of the actual contactor device is constructed by combining the abovemen-tioned fundamental symbols for mechanical connections, control circuits, etc.

Mechanical interlocking should be indicated by notes.

Note 24.2A—The asterisk is not a part of the symbol. Always replace the asterisk by a device designation.

46 Machine, Rotating

*The broken line (– – –) indicates where line connection to a symbol is made and is not a part of the symbol.

48 Meter Instrument

As indicated in Note 48A, the asterisk is not part of the symbol and should always be replaced with one of the letter combinations listed below, according to the meter’s function. This is not necessary if some other identification is provided in the circle and described in the diagram.

AAmmeterAHAmpere-hourCMAContact-making (or breaking) ammeterCMCContact-making (or breaking) clockCMVContact-making (or breaking) voltmeterCROOscilloscope or cathode-ray oscillographDBDB (decibel) meterDBMDBM (decibels referred to 1 milliwatt) meterDMDemand meterDTRDemand-totalizing relayFFrequency meterGGalvanometerGDGround detectorIIndicatingINTIntegratingμA or UAMicroammeterMAMilliammeterNMNoise meterOHMOhmmeterOPOil pressureOSCGOscillograph stringPHPhasemeterPIPosition indicatorPFPower factorRDRecording demand meterRECRecordingRFReaction factorSYSynchroscopeTLMTelemeterTTemperature meterTHCThermal converterTTTotal timeVVoltmeterVAVolt-ammeterVARVarmeterVARHVarhour meterVIVolume indicator; meter, audio levelVUStandard volume indicator; meter, audio levelWWattmeterWHWatthour meterMeter Instrument.

58 Path, Transmission, Conductor, Cable, Wiring

63 Polarity Symbol

+

63.1

Positive

-

63.2

Negative

Polarity Symbol.

76 Switch

See also FUSE (item 36); CONTACT, ELECTRIC (item 23); and DRAFTING PRACTICES (items 0.4.6 and 0.4.7).

Switch symbols may be constructed using the fundamental symbols for mechanical connections, contacts, etc.

In standard procedure, a switch is represented in the nonoperat-ing, or deenergized, position. In the case of switches that have two or more positions in which no operating force is applied and for those switches (air-pressure, liquid-level, rate-of-flow, etc.) that may be actuated by a mechanical force, the point at which the switch functions should be described in a clarifying note.

In cases where the basic switch symbols (items 76.1–76.4) are used in a diagram in the closed position, the terminals must be included for clarity.

86 Transformer

*The broken line (- — -) indicates where line connection to a symbol is made and is not a part of the symbol.

1

Review Definitions

Definitions are covered in Article 100 of the National Electrical Code (NEC). The questions that follow will not cover all of the definitions but only the more pertinent ones. The answers given here are the author’s. Refer to Article 100 of the NEC for the official definitions. Some definitions appear in the Code elsewhere than Article 100 (see NEC, Index).

1-1 What does “accessible” mean as applied to wiring methods?

It means readily available to inspection, repair, removal, and so on, without disturbing the building structure or finish; not permanently closed by the structure or finish of a building.

1-2 What does “accessible” mean as applied to equipment?

It means equipment that may be readily reached without climbing over obstacles—that is, not in locked or other hard-to-get-at areas such as panelboards mounted inside kitchen cabinets or mounted in or on the walls above washers and dryers or in closets or bathrooms; service-entrance equipment that can be reached only by going into a closet, behind a stairway, or around some other obstacle. All of these would be termed “accessible.”