Electrical Certification Test.PDF

Hlecfrical

ter*fifflcaffi$Er

Test amd Review

Booklet

Electrical Certification Test and Review

This test is based on the L999 National Electrical Code@,

a

resource

of over 20000

electrical test questions,

and dozens

of

electrical books and articles. Each Code question is researched

using electronic

versions

of the 1999 NEC@ and the 1999

IYEC@

Handbook including the cross reference

to the 1996

hl-Ec@.

This booklet consists

of 20 tests with 20 questions

Answers and explanations

+ text reference

to the 1999 I\[EC

l .

Test Taking Tips

Calculate

the time per question as soon as you start your test. This is

important so you will not spend too much time on one question. If

thr." are 70 questions

and an allotted time of four (4) hours, then the

time per question

is 4 x SQ

minutes divided by 70 or 3.4 minutes per

qu.rtiott. If there are 70 questions

worth one point each and 3

di"gr"-t worth 10 points each, then find the time allowed per point.

tlrii woutd be (4 x 60) divided by 100 or 2.4 minutes per point. Then

allow 24 minutes

(10 x2.4) for each diagram and2.4 minutes per

question.

Answer the easier

questions

first. Leave the more difEcult ones and

mark them so you can go back to them. Do not spend

too much time

on one question. This is a classic

mistake!

Answer all questions

even if you have to gUess. Remember

you have

a 50 percenfchance

of getting a trre false question correct by simply

guessing.

Read.t.h question

carefully. Do not skim over questions.

Read each

word!

Find out if the test is open book. If it is, index your Code Book and

practice using the indexes. Index the Book before begiffIing your

studies.

o lndex Table 250-L22

for finding equipment

grounding wire

sizes.

o lndex Table 250-66 for finding grounding electrode

and

bonding

jumPer sizes.

o Index Table 8 in Chapter

9 for finding circular mil areas,

dimensions

of bare conductors,

and DC resistance

of

Conductors.

o lndex Section

240-6 for finding the standard

circuit breaker

and

fuse sizes.

o lndex Table 430-148,

Table 430-150,

and Table 430-152

for

sizing motor circuits.

Practice

looking up Code questions.

You should be able to find the

answer

to any single answer

Code question

in less than 3 minutes.

More complex

questions,

especially

calculation

problems, require

more time and more Code sections.

Begin your examination

by unloading

the formulas

onto a blank piece

of paper. This is perfectly

legal and saves

time later when you may

not be able to remember

the particular

formula.

) J . 4. l - J I

6 .

7 .

8. For each and every question try these four steps.

o Locate the given infonnation in the question.

o Locate any unknown infonnation necessary

to solve the

question.

o Locate the ''KFY' word or phrase in the question.

o If you cannot find the answer using the

"KEY", and it is a Code

question search the Code index for ttre

"KEYrr word.

9. After completing the test go back and scan it to make sure you have

answered

every question and have not skipped pages or blanks.

lO.If a question

requires

the use of a Table, be sure and read the notes to

the table. Also remember

each Table has a Section number the same

as the Table number. The section will have additional infonnation

pertaining to the Table.

1 l.It is strongly recommended

that you study no more thaa2 hours per

day and shrdy for about 40 hours prior to taking the journeyman

electrician test, and about 80 hours for the master electrician test.

l2.Be careful about writing formulas in your Code Book. If you are

allowed to use your own Code Book at the exam, it may be checked to

make sr:re that it does not have mirterial written in it, or you may be

given a Code book to use.

l3.If you are allowed to bring a calculator

to the exam buy one and bring

it.

l4.Get plenty of rest before taking the test. It is also a good idea to

practice looking up Code questions

for one hour just before taking the

Test. This increases

test scores

by as much as ten percent for some

people

^ , I

Must Know List for Taking Electrician's Examinations

a a a a

a

Know Ohm's Law and the Power formula. The Basic electrical theory pag€ covers

these fairly well. Buy Ugley's or Ferm's for a more thorough coverage. Know

everything on the Theory page as a minimum.

Know how to hookup nine lead star and delta wound induction motors. Know how to solve turns ratio transformer problems.

Know how to hook up three and four way switches.

Know how to determine motor branch cirpuit and feeder protection and wire sizes.

Know key Sections in the Code. These include:

l. Article 100 is definitions.

2. Article 90 purpose and scope of the Code.

3. Artiole 110 rules for electrical installations such as work clearance and

equipment space rules.

Article 210 for branoh oircuit calculations. Articte 220 for service and feeder calculations. Article 230 for services.

Article 240 is for overcurrent protection.

Article 250 is for grounding.

Articte 300 for general installation rules and methods.

Section 300-5 for burial dePths.

Article 310 for ampacity tables.especially Table 310-16 with notes.

Article 318 for cable traY.

Articles in Chapter three for raceways. Article 348 for EMT.

Article 346 for zugrd Metal Conduit. Article 430 for motors.

Article 440 for refrigeration equipment and motor-comPressors.

Article 450 for generators. Article 490 for high voltage

Article 501 for Class I, Division I and2locations.

Article 600 for signs.

Know that for commercial building a 20 ampere outside sigrr circuit is

required and the load is 1200 volt-amP€res.

know that emergency and standby _{Power systems} requirements in Articles

700, 701, and702. These are extensions of Article 445 on generators.

know that for Hospitals there are additional requirements for emergency

power in Article 517.

25. ifuow that Appendix D has examples for load calculations and motor

circuits. Read and studY them.

26. Know that conduit and conductor dimensions areas, etc., are in Chapter nine,

but for all conductors of the same size the fill tables are in Appendix C.

27. Know that Class 2, Class 3, and Class I circuits and other "low voltage"

requirements are in Article 725.

Basic Electrical Theorv

Series Direct Current Circuit Rules

Rule #1: The same current flows through each part of a series circuit. Rule #22 Total Resistance of a series circuit is equal to the sum of the

individual resistances.

Rule #3: The total voltage across a series circuit is equal to the sum of the individual voltage droPs.

Rule #4: The voltage drop across a resistor in a series circuit is proportional to the size of the resistor.

Rule #5: The total power dissipated in a series circuit is equal to the surn of the individual power dissapations.

SUMMARY OF OHMS I'/IW FORMUI-A9

AMPERES

=

_ffi+ANCE

RESTsTANCE

=

_ff"*".

Parallel Direct Current Circuit Rules

Rule #1: The same voltage exists across each branch of a parallel circuit and is equal to the source voltage.

Rule #2: The current through a branch of a parallel network is inversety proportional to the amount of resistance of the branch.

Rule #3: The total current of a parallel circuit is equal to the sum of the currents of the indMdual branches of the circuit.

Rule #4: The total resistance of a parallel circuit is equal to the reciprocal of the sum of the reciprocals of the indMdual resistances of the circuit.

Rule #5: The total power dissipated in a parallel circuit is equal to the sum of the individual power dissapations.

SUMMARY OF PAR'4LLEL

CIRCUIT RULES

TOTAL VOLTAGE = E(1) = E(2) = E(3) ...etc.

VOLTS

TOTAL RESISTANCE = _AIVfPERES

G l

TO DEEERT'fINE THE TOtrAJ, RESISTAI{CE fN A PARiAILEIT CfRCUIT WI{EN THE I.OTAIJ Ct'RREbIT ATiID TOTAT. VOLTAGE ERE UNKNOI$T USE ETTIIER OF fHE FOLIOIIII}IG FORMULAS:

R r -

l + 1 + l * . . . e t c

RI R2 R3

FOR TWO RESISTORS IN PARALLEL USE

THIS FORMULA CALLED TIIE

''PRODUCT

OVERTM SLIMII

R(1) t'R(2) R r = R(t)+R(2)

POIiIER IN SINGI.E PHASE RESISTI\ZE CIRCUTTS

WHERE PO!{ER FACTOR IS 1OO PERCET'NT

(rmsn EoRMtItAs ARE COM!{ON&I USED lO SOL\'E MOST CTRCUIE PtrilER

PRoBr.EMs! ou lesrs)

trO DETERI4INE TEE POWER CONSUMED BY All TNDTVIDUAJ, RESISTOR rN A SERIES CTRCUIT USE trEIS FORMT]I,A:

t 2 p o g t E R - _{r X R}

_ 8 2

PO!{ER - R

TO DETIIRMTNE trEE TOTAI1 PO?|ER CONSIIMEID BY AII BIDTWDUAJ., CXRCTTIT USE TEIS FORMTII,A:

por{ER - E (TOTAMLTAGE) x I (TOTAI CURRENT)

RIII,TS OF TEUMB:

' _{TEE IOTAIJ RESXSTAIICE OB RESISTORS XN PARiAJ.LEI. IS ALI$AYS} r.nSS TIIA}I TIIE \lALItE OF AI\TY ONE RESISTOR.

. _{TIIE TOTAIJ RESISTA}ICE OF PARATI'EL RESIStrORS TEAT ARE AII,} TEE SAME V?II,I'E IS TEAtr VAJ,I'E DTVTDED BY IT'EE NUMBTR OE' R E S X S T O R S .

' _{AI.VIB'YS USE TEE PRODUCT O\IER SUM RIII"E trO EIREiAK DOWN gWO} PARJAI.I,EIJ RESISEORS NflTO ONE RESISTOR. TIIIS TS MUCE XIASIIIR TEAI{ TRYTNG rO SOL\IE XJARGE A^IrGEBRAfC EXSRTSSIONS. ' _{146 !{ATTS IS EQUAL EO ONE EORSEPOI|ER}

' _{EFFTCTENCY rS EQUAL TO OTXPPUT DMDIID BY INPLTII} . _{TN I}IDUCTT.\IE CTRCI'IBS CURRE}III' I,AGS VOIJIA@.} O _{IN CAPACITIVE CXRCUITS CURREDI1I ]JEEDS VOI,TAGE.}

o _{POTVER FACTOR IS A MEliASttRE OF BOW FAR CURRENT IJEiADS OR} LAGS VOLTAGE.

I

I

POVTER IN ALrERNAEfNG

CUre

POWER FACTOR IS NOT 1OO PERCEtflI

POWER = E x I x POWTR FACTOR (ron snrer's PEASE)

powER = E x I x 1.132y- PO!{ER FACtrOR (ronrmsr PEA.SE)

THIS POWER IS AISO CEJ.I.ED trRI'E POITER OR REAI POWER AS OPPOSED TO APPEREMT PO!{ER FOT'ICD BY CEIJCuILATING VOLtr-AMI{SRES '

VOLT-AI'{PER.ES = E x I (ron srNer.e euaso)

VoLT-AMPE,RES = E x I x 1.132 (ron rmna rnnse)

IE CJA}T READIIJY BE DETERMTNED BY AI,GEBRA EEAT

P O W E R F A C T O R : _{APPARENT POWER}

MOTOR APPLfCATION FOR!'IqI{4g

IIORSEPOI{ER = t.232 x vol,ts x,rrMPERES x gtr'ptctexcY x

(for three _{Phaseoowerfacjqt}

motors | 746

THREE PHASE A},IPERES = 746 X HORSEPOWER

(for rhree phase motors) 1J32x voLTS x EFFICIENCY x POWER FACTOR

TEREE PEASE SEAR OR Y

I{OTOR UERK:INGS E}ID CONNECTIONS

COXNECTTONS FOR ![I}fE I.IED :TEREE PEA,SB }'C)|IORIg

STAR CONNECTED

-[

Lt". ,

-f

Ltn. 3

-i-

Together

a , & 8 l - 3 & e I

4 & 5 & 6

i - 3

t -

4 & , 7 , 5 & 8 , 6 & 9

l

2

*f

v

5 }1 ,-i \ 6

l^

\ 1

r & 7

:

i

EERTE PEASE DEI.TA

DELTA CONNECTED

I,IOEOR CONTROI..I.ER W:[:TE TEREE StrARE SEOP StrA:IIONS

(EOI.DrNG COInDACTS NOT SEOIIN)

CRANSFOR!,ER TT'TTNS RATTO

Ep volts

Tp Turns

E s v o l t s '

Ts Turns

Ep - T-p

Es

Ts

Where Ep is primary voltage Es is secondary voltage

Tp is number of turns in p.imaty Ts is number of tums in secondary

Maximum Horsepower for NEMA-Rated Motor Starters

lls I Zsg l2o8t2so

l46ots7s

V o l t i V o l t l V o l t

t oo rrv-lr

--[G--P

t . )

_{i 10}

i r

i r . t j r o n s ; 2 s

i - t - l

@ t

r=-l

@t

NEMA RATING FOR ENCLOSURES

NEMA and other organizations have established standards of enclosure construction for control equipment. In general, equipment would be enclosed for one or more of the following reasons:

L Prevent accidental contact with live parts.

2, Protecl the control from harmful environmental conditions'

3. Prevent explosion or fires whictr might result ftom fre electrical arc caused by the control. Common types of enclosures per NEMA classification numbers are:

N E M A I . G E N E R A L P U R P O S E

The general purpose enclosure is intended primarily to prevent accidental contact with the enclosed apparatus. lt'is iuitabte for general purpose applications indoors where it is not exposed to unusual service cirnOitions. A NEMA I encloiure serves as protection against dust and light indirect splashing, but is not dusttight.

NEMA 3. DUSTTIGHT, RAINTIGHT

This enclosure is intended to provide suitable protection against specified weather hazards. A NEMA 3 enclosure is sui+rable for applibtion outdoors, on ship docks, canal and construction work, and for application in subways and tunnels. lt is also sleet-resistant.

This enclosure protects against interference in operation of the contained equipment due to rain, and resists damage from exposure tdsbet. lt is designed with conduil hubs and extemal mounting, as well as drainage provisions.

NEi,IA 4.WATERTIGHT

A watertight enclosure is designed to meet the hose test described in the following note: "Enclosures shall be tested'by subjection to a stream of water. A hose with a one inctr node shall be used and shalldeliver at least 65 gilons per minute. The water shall be directed on the enclosure ftom a distance of not less than 10 feet and ior a pehoO of five minutes. During this period lt may be djrected in any_o-ne or more directions as desired. Therd shall be no leakage of water into the enclosure under these conditions.'

A NEMA 4 enclosure is suitrable for applications outdoors on ship docks and in dairies, breureries, etc. NEMA 4X . WATERTIGHT, CORROSION.RESISTANT

These enclosures are generally constructed along the lines of NEMA 4 enclosures except they are made of a material that's highlf resistai'rt to corrosion. For this reason, they are ideal in applications sucfi as pap€r mills, meat pacrung, tertllizer and cfiemical plants where contaminants rr'rould ordinarily destoy a steel enclosure over a period of Ume.

NEMA 7 . HAZARDOUS LOCATIONS . CLASS I

These endosures are designed to meet the application requirements of the National Electrical Code for Class I ha'ardous locationi. ln this type of equipment, the circuit intemlption occurs in air.

"Class I locations are those in which flammable gases or vaPorc are or may be present in the air in quantities sufftcient to produce explosive or Qnhbble mixtures.'

NEIIIA 9 HAZARDOUS LOCATIONS - CI-ASS II

These enclosures are designed to meet the application requirements of the National Electrical Code for Class ll hazardous locations.

"Class ll locations are those which are hazardous because of the presence of combustible dust."

The letter or letters following the type number indicates the particular group or grgups of hazardous locations (as defined in the National Electri6it Code) for which the enclosure is designed. The designation is

incomplete without a Euffx letter or letters. N E M A 12.INDUSTRIAL U S E

The NEMA 12 enclosure is designed for use in those industries where it is desired to exclude such materials as dust, lint, fibers and f,yings, ol see page or coolant see page. There are no conduit openings or

knockouts in the enclosure, and mounting is by means of flanges or mounting feet. NEMA I3. OILTIGI'TT. DUSTNGHT

NEMA 1 3 enclosures are generally of cast construction, gasketed to permil use in the same environments as NEMA 12 devices. ThJessential difference is that, due to its cast housing, a conduit enty is provided as an integral part of the NEMA 13 endosure, and mounting is by means of blind holes, rather than mounting brackets.

1.

Electrician Practice Test 1

In Class 1, Division 7 locations, conduit seal shall be placed a maximum of

inches _{Jrom an enclosures lor arc producing devices.}

r - { 1 2 (' b) t8 r c 1 2 4 c' d) 30

What length is requiredfor the pullbox in the diagram below? The box is used with 480 volt conductors.

ay 32 inches

D24 inches

c; 48 inches d) anY length

Pull Box fror

uncjer 600 voh circuit

conductors hlo.4 and lcr.rQer

?

t l !

? Whut is the load that can be usedfor the semice calculationlor o dwelling '

unit when the Range has a nameplote rating of 13 KV? r a ; 1 3 k w r b) 8'4 hr/ ? c ; 8 h a " t-

d) none ofthe above

/ What size equipment grounding conductor is requiredfor a circuit

protected with a 50 ampere circuit breaker? l^ a) No' 12 coPPer ' b) No' 1o coPPer t* c) No' 8 coPPer

5. What is the highest voltagefor a Class I power limited circuit?

r a; 1'000 volts (^ b; 3o volts . c1 24 volts r

6.

What is the missing voltage in the sketch below? a; 120 volts U; 120 volt's c1 1200 volts d; 12,000 volts

120

votts

1 00 Turns

Vottage

is

1 ,000

Turns

Wtat size Rigid Metal conduit is permittedfor thefollowing 9 conductors? 4 THVN #1, CU, 2 RHll/ (covered) #8 CIl, 3 RHW (covered) #6 Ca

a1 1 1/2 inch U; 1 1/4 inch

e 1 Il2 inch and 1 1/4 inch

d) None of the above

lV'hat is the el/iciency of a motor which draws 4,5 kilowatts from the line

and delivers 5 horsePower? r a) 80 Percent c 5;83 Percent

r

C ('

7.

{ (-a

8.

9, Power Factor con be defined as: r

a) True Power divided by Apparent Power. '

by Apparent Power divided by True Power '

s1 Appatent Power divided by volts x amperes

t n What is the powerfactorfor a three phase system operating when the

'' t"

wafirneter reads 6,000 watts, the voltneter reads 208 volts, and the ammeter reads 20 amperes? c a) .90 or 90 Percent r u; 1.0+ or 104 Percent (' c) .83 or 83 percent

t f Mtat is the powerfactor of a 8000 watt load connected to a 240 volt AC

L L '

single-phase circuit if the current is 36 amperes?

c a) '8 or 80 Percent c b) .93 or 93 Percent r c; 1.0 or 100 Percent

l !

.

t ). For theJigure below tf No. I or larger conductors are installed in the '-'

raceways dimension X shall be _inches minimwn The box is rcedlor

splices and doe not have the cubic inch dimensiotts marked on iL

a) 18 inches b) 16 inches

e 24 inches

C

73, For the 4-wal Switch, which is the correct hookup? r a ; D t o T , E t o & F t o T , G t o s c b ; D t o S , E t o & F t o T , G t o W c c ; D t o R , E t o T , F t o s , G t o w

4imy s'rvfuh

To 4-Way

Sw

t

i

( :

l

, ,t A dwelline has a floor areaof 2200 sq. ft., exclusive of an unfnished ceilar r-ic

not adaptalle for future use, unlinished attic, and open porches. Appliances

are a lj-kW range and a 5.5-kW, 240-V dryer. Assume rzmge and dryer kW

ratings equivalent to kVA ratings in accordance with Sections 220'18 and

2z}-lg.Computed Load [see Section 220-101

Fill in the following information:

General Lighting Load: sq. ft. at - VA per sq. ft. =

Minimum

Number of Branch Circuits Required:

GeneralLigbtingLoad: VAI l20V:-A

: General Lighting Load: YA I 120 V : - A

-.i ThiJrequires_ 15-A 2-wire or- 20-A,2-wire circuits

Small Appliance Load: 2-wire, 20-A circuits

Laundry Load :One 2-wire, 20'A circuit

one additional bathroom 20 ampere circuit is also required.

Minimum Size Feeder Required :

General Ligbting - VA VA Small Appliance Laundry Total 11100 VA VA at 100% 3000 VA VA - 3000 VA = VA at o/o is Net Load - VA Range - VA Dryer- VA

Net Computed Load - VA

Net Computed Load for 1201240-V, 3-wire, single-phase service or

y A l 2 4 0 V = _ A

Net computed load exceeds 10 kVA.

conductors to be - A.

Would require service VA

VA

VA

feeder

Calculation for Neutral for Feeder and Service:

Ligbting and Small Appliance Net Load

Ranee: VA at 70Yo is 5600 VA

Dryer i - VA at 70% is

Total - VA

Load for Neutral:

VA

What is thetinal computed loadfor the neutral in the above load calculation? r a1 65'9 r b) 63'7 r c1 loo r d ) 1 1 1

15. The correc't hookupfor the 3-woy swilch below is:

r a 1 A t o X , B t o z , c t o Y r b ; A t o Y , B t o x . c t o z r c ) A t o Z , B t o Y , C t o X r d ; A t o Z , B t o X , C t o Y

S U P P L Y

To 4-way

Switch

&iiay s'sribh

16.

in the diagran below.Connect the delta wound 480 vott motor leadsfor the high voltage windings (* a7 g_7, 4-6,9-9, 54 r' b) 4_7,5-9, 6-9 c c; 4-9, 6'8,5'7

77, Find the correct size ventilated cable troyfor the diagram below. {^ a; 6 inches r b) 12 incbes r c) 18 inches ' d)24 inches Gr,sr 4/€ rElultloon4nctot e e b l e a E a c f i c a b l , e l a g incfi es iar dierns er

\

- Und'f, drra rnultiaon€tucto" I cables. E.=ctr +s{'e ;s \ r incn in ,risrraer

\

\

l

\ l

1 8 .

Find the voltage across the 5 ampere load afier the neutral is opened Botlt

loads are resistive and the powerfactor is 1.0.

(- a; 180 volts c b1 120 volts ' c; 0 volts 2 4 O v . a h J 1 2 9 v € { : l 3 € r v i € .

, O Find the size of inverce time circuit breaker requiredfor thefeeder r '/t

protecting theJoltowing polyphase induction moton. These motors are 'Design

B and-have a S-erviii Factor of 1.15 and are individually protected

with inverse time circuit breakers. c a; 150 amPere r- b) 175 ampere r c; 200 ampere q : J I I I

20.

How many cubic inches is requiredfor thefollowing box? AII conductors are No, 11 and there are no iiternal clamps,

r { Qcubic inches (^ b) 16 cubic inches (- c) 18 cubic inches ' d) 20 cubic inches

Electrician Practice Test L

A}[SWBRES

#l b (18) Conduit seals

shall be installed

within 18 in. from the

enclostue.

Only explosion

proof unions' couplings,

reducers,

elbows, cappea

elbbws, and conduit bodies such &s L, T, and X

types not larger than the fiade size of the conduit are permitted

ut.t seal.

Text Reference

section

501-5(a)(1)

#2 a (32 inches) tn sfraight

pulls, the length of the box shall not

be lesi than eight times the trade diaureter

of the largest

raceway'

Text Reference

sectio

n 37 0'28(aX

_{1 )}

#3 b (8.41n

,) 8 kw + 5 percent

of 8 kw is 8'4 kw'

Text Reference

section

table 220-19

Note 1

#4 b CIo. 10 copper)

Table

250-122

lists aNo. 10 copper

for a 50

ampere

circuit breaker.

Text Reference

section

250'L22

#5 b (30 volts) class 1 power

limited

circuits

shall

be supplied

from a source

ihat has Lrated

output

of not more than 30 volts and

1 00

0 volt-amperes.

Text Reference

sectio

n 7 25 -21

(a)

#6 c (1200

volts) l20A/oltage:

100

/1000;

voltage

= (120 x 1000

)/ 100,

voltage

: 1200

volts

#7 c (l % inch & | y4 inch) Problem: What size Rigid Metal conduit is

permitted for the following 9 conductors?

+ nrw}I #12 cIJ,2 RI{W (covered)

#8 cu, 3 RITW (covered)

#6 cu

From Table 5:

Area of #12 TIIV/N is .0.133

x 4 = .0532

Area of # 8 RI{W covered

= .0835

x2: .167

Area of #5 RHW covered

= .1041

x 3 = .3123

Total area: .5325

sq. inches

tn Table 4 for Rigrd Metal Conduit find the first number larger than .5325 that

is 0.610 in column for over 2 wires

40%-This corresponds

to L ll4 inch conduit.

A I I/2 inch conduit would also satisff the requirement.

Answer: C both I l/4 and 1 l/2 nch conduits

can be used.

Text Reference

section Chapter

9 Table l, Table 4, & Table 5

#8 b (83 percent)

efficiency: (5 x 746watts)

/ 4,500 watts

Basic Electrical Theory in aNutsheLl

See Handout

Text Reference

section Basic Electrical Theory

#9 a (True Power divided by Apparent

Power) True Power :

watts, Apparent

poweFvolt-amperes.

PF : watts/ volt amperes

Text Reference

section

Basic Electrical Theory

#10 c (83 or 83 percent)

PF = 6,000

I (208*20*1.732)

Text Reference

section

Basic Electrical Theory

#11 b(.93 or 93 percent)PF:8,000

I (240 volts x 36 amperes)

Text Reference

section

Basic Electrical Theory

#12 c (24 inches)

Use larger of (6 x 3) + 3 +3 : 24 inches

or (6 x

2 ) + 2 + l + 1 : 1 6 i n c h e s .

D i m e n s i o n X s h a l l b e 2 4

i n c h e s .

Text Reference

sectio

n 37 0'28(aX2)

t

#14 b (63.7) This problem

is alnost identical

to Example

D1(a) in Appendix

D of the 1999 Code. This dwelling has a floor arcaof 2200 sq. ft., exclusive of an

rrnfinished cellar not adaptable for future use, unfinished attic, and open porches.

Appliances are a 12-kW range and a 5.5-kW, 240-V dryer. Assune range and dryer kW

ratings equivalent to kVA ratings in accordance with Sections 220-18 aad220'

1 g.Computed _{Load [see Section 220-l0l}

General Lighting Load: 2200 sq. ft. at 3 VA per sq. ft. = 6600 VA Minimum Number of Branch Circuits Required

[see Section 210-11(e)(1)] General Ligbting Load: 5600 VA / l20V: 55 A

This requires for:r l5-A 2-wire or three 20-A" 2-wire circuits

Small Appliance Load: Two 2-wire,20-A circuits [see Section 210-11(cX1)]

Lar:ndry Load:One 2-wbe,20-A circuit [see Section 210-11(c)(2)]

Batlrroom Branch Circuit: One 2-wire,20-A circuit (no additional load calculation is

required _{for this circuit) [see Section} 210-11(cX3)]

Minimum Size Feeder Required [see Section 220-10]

General Lighting 6600 VA Small Appliance 3000 VA Laundry 1500 VA T o t a l 1 1 1 0 0 V A 3000 VA at 100% 3000 VA I I 1 0 0 V A - 3 0 0 0 V A : 8 1 0 0 V A a t 3 5 Y o i s 2 8 3 5 V A Net Load 5835 VA

Range (see Table 220-19) 8000 VA

Dryer (see Table 220-18) 5500 VA

Net Computed Load 19,335 VA

Net Computed Load for 1201240-V, 3-wire, single-phase service or feeder

1 9 , 3 3 5 _{V A ,240 V = 80.6} A

Net computed load exceeds 10 kVA. Section 230-42@) would require service conductors

to be 100 A.

Calculation for Neutal for Feeder and Service

Lighting and Small Appliance

Net Load 5835 VA Range: 8000 VA at70%o (see Section220-22) 5600 VA Dryer : 5500 YA at70% (see Section220-22) 3850 VA Total 14,550 VA

Computed Load for Neutral

#15 c (A to Z, B to Y, C to X) See Diagam

&vay svribh

To 4-way

Switch

#16 b (4-7,5-8,

6-9) Text Reference

section

Basic Electrical

Theory See

Diagrarn

O v e r 4 / o m u l t l c o n d u c t o r c a b l e s . E a c h c a b l e l s 2 I n c h e s I n d l a m e t e r

!

#17 b ( l2_tqshes

Text Reference

section

318-9(a)(2)

and Table 318-9

# 1 8 a ( 0 v o l t s ) R f o r 1 5 a l o a d

: 1 2 0 1 1 5 : 8 ohms;

R f o r 5 a lo a d

: 1 2 0 1 5

: 24 Neutral open l: 240 /(8 + 241

: 7 .5 a; E across

5 a load :7 .5 ax 24

--180 volts see diagram

N e L J t r a l o r g r o u n d e d c o n d u c t o r

Solution

Problem: Find the voltage across the 5 ampere load after the neutral is opened.

First find the resistance of each load:

l5 ampere load: V o l t s : 1 2 0 R : E / I R: 120 volts / l5 amperes R : 8 o h m s 5 ampere load: R: 120 volts / 5 amperes R : 2 4 o h m s

When neutral is open the two resistors are in series and the Total Resistance is 8 + 24 or 32 ohms'

The voltage is240 volts across the two resistors in series.

To find the curent after the neutral opens:

I= 24Q volts / 32 ohms

[ = 7.5 urmperes

The voltage across the 5 ampere load that has a resistance of 24 ohms is:

E = l x R

#19 b (175 amDere)

see

di

.'^.

Problem: Find the size of inverse rime circuit breaker required for the feeder protecting

the following polyphase induction motors. These motors are Design B and have a

Service Factor of I .15 and are individually protected with inverse time circuit breakers.

This is a motor feeder circuit. There is a motor feeder Example D8 in Appendix D of the Code.

Motor Circuit Conductors, Overload Protection, and Short-Circuit and Ground-Fault

Protection

(see Sections 240-6, 430-6,430-22,430-23,430-24, 430-32,430-34,430'52, and 43042,

Tables 430-150 and 430-152)

Feeder Short-Circuit and Gror:nd-Fault Protection

The rating of the feeder protective device is based on the largest branch-circuit protective

device plus the sum of the full-load currents of the other motors [see Sections 240-6 and

a30-62(a)l

For the 5-hp motor FLA is 7.6 'mperes from Table 430-150.

For the 15-hp motor FLA is 21 arnperes from Table 430-150.

For the 40-hp motor FLA is J) ernpercs from Table 430-150.

52 x 1.25= 65 amperes

65 + 2l + 7.6 = 93.6 arnperes

The branch circuit protective device for the 40 hp motor is based on Table 430-152 is 250

percent times 52: 130 amperes. By Section 240-6 the next larger standard size CB is

150 amperes.

Then for the feeder Circuit Breaker: 150 + 2l + 7.6 = 178 amperes.

The nearest standard fuse that does not exceed this value is 175 A [see Sections 240-6

and 430-62(a)1.

#20 b (16 cubic inches)

see di

Problem:

How many cubic inches

is required

for the following box? All

conductors

are No. 14 and there are no intemal clamps'

Conductor Count Switch :2 '

Gror:nding conductors:1

Conductors that originate outside the box and terminate or are spliced in the

. b o x : 5

'

Total:8

;

't

The cubic inch area required by Table 370-16(b) for a No. 14 is 2 cubic inches. -i _{The cubic inch capacity required is 2 cubic inches x 8 or 16 cubic inches.}

:

")

_{Answer is 16 cubic inches.}

i

Reference:

(b) Box Fill Calculations. The volumes in paragraphs (1) through (5), as applicable, shall be added together. No allowance shall be required for small fittings such as locknuts and bushiirgs.

(1) Conductor Fill. Each conductor that originates outside the box and terminates or is spliced within the box shall be counted once, and each conductor that passes through the box without splice or termination shall be counted once. The conductor fill, in cubic inches, shall be computed using Table 370-16(b). A conductor, no part of which leaves the box, shall not be counted.

Exception: A:r equipment grounding conductor or conductors or not over four fixnue wires smaller than No. 1.4, or botb shall be permitted to be omitted from the calculations where they enter a box from a domed fixture or similar canopy and terminate within that box.

(2) Clamp Fill. Where one or more internal cable clamps, whettrer factory or fietd supplied, are present in the bo6 a single volume allowance in accordance with Table 370-16(b) shall be made based on the largest conductor present in the box. No allowance shall be required for a cable connector with its clamping mechanism outside the box.

(3) Support Fittings Fitl. Where one or more fxhrre studs or hickeys are present in the bo>r, a single volume allowance in accordance with Table 370-16(b) shall be made for each type of fitting based on the largest conductor present in the box.

(4) Device or Equipment Fill. For each yoke or strap containing one or more devices or equipment, a double volume allowance in accordance with Table

370-16(b) shall be made for each yoke or strap based on the largest conductor connected to a device(s) or equipment supported by that yoke or strap.

(5) Equipment Grounding Conductor Fill. Where one or more equipment grounding conductors or equipment bonding jr.mpers enters a box, a single volume allowance in accordance with Table 370-16(b) shall be made based on the largest equipment grounding conductor or equipment bonding jumper

present in the box. Where an additional set of equipment grotrnding conductors, as permitted by Section 250-L46(d), is present in the box, an additional volume allowance shall be made based on the largest equipment grounding conductor

Electrician Practice Test 2

I. In the diagram below the total resistance is and the value of R3 is

a) 20,10.7 ohms b) 20,19.7 ohms c) 20,20.7 ohms d ) 1 0 , 3 0 o h m s

(-r

l a 1 0 o h m s _{I = 6 a m p e r e s} R t = itoialreslslanc e)

) Wat is the ampacity of 12 No. 12 THHN copper conductors in a I0feet long

-'

EMT raceway where there are 9 current carrying conductors and the ambient

temperature is 42 degree C? (Select nearest answer)

f (-a) b) c) 10 amperes 15 amperes i 8 amperes 120 volts _{20 ohms}

I '^"Tl

R2 1 0 o h m s

2 lVhat is the allowable ampacity of each No. 6 THW copper conductor if there ro

are l0 current carrying conductors in a 21 inch long rigid conduit nipple in a room where the antbient temperature is 55 degrees C? (Select nearest answer)

r a) 65 amPeres r b) $J amPeres (^ c) 50 amPeres r O 44 amperes

/ Find the size EMT nipple required to enclose 3 each 500 kcmil THHN

'rr

conductors bethteen wo

Panek-c a) 1 1/2 inch r b) 2 inch r c) 3irch ' d) 3 1/2 inch

( What size rigid steel conduit is requiredfor 1 each 4/0 XHHV/ and I each

cro

No. 3 bare iquipment grounding conductor if the raceway is 12feet long? c a) I ll2 inch r- b) 2 inch (. c) 2 ll2 inch (- d) 3 inch ' e) 1 inch

.

6. Junction boxes shall be '

C a) accessible '. _(- b) readily accessible r .; visible (-

d) inside removable Panels

. i

n The type of lampholder required in a branch circuit in scess of 20 amPeres

/' ,ioi6, ' '.

c a) brass l- b) Porcelain coated (-

c) not an interchangeable tYPe

'

d) heavY dutY

g. Ilnless an ucepted load as speciJied by the Code, a 56 ampere load shall be

protected bY a -fuse. t- a) 50 r b) 60 r* c) 70 (- d) 80

O fn a washdown area a metollic rucewoy shall be spacEd not less than "

inchfrom the walls. r a) ll8 c b ) l l 4 (- c) l/2 c d) 314

I n Given: Three (3) 500 kcmil Type THHN copper conductort in a raceway at

L v'

70 degrees C. The maximum allowable current in each conductor b

-amPefes.

r'

t

r'

1 a) b) c) d) 249 409 430 705

t I Alixture that weighs more than -pounds shall be supported

^ f

independentty of the outlet bon

r a ) _{4 0}

r

b) 50

c c ) _{6 0}

7 2. An AC-DC general use snap switch may be used wilh inductive loads at

-percent of its amPere rating at the applied voltage'

c a) 40 c b ) _{5 0} e c ) _{7 0} (- d) 80

, 2 When utilized as ou&ide bronch circuib andfeeden, overhead conductott t "'

fo, 600 volts or less, for spans up to 50 feet, shall not be less than

copper. (- a) No. 14 c b) No' 12 r c) No' 10 r * O N o . g

t / Conductorc of light and power systems of 600 volts or less may occupy tlte

rq'

ioit enclosire, without regard to whether the individual circuits are AC or

DC, only where all the conductors are -' c

a) insulated for the ma:cimum temperature within the enclosure.

,^ insulated for the maximum voltage of any conductor within the

,

b) _enclosure

'

c) insulated for the maximum of 300voits

r'

I < When utilized in overhead services, without any excePtions, conducton t Jo

shalt not be smaller than No. coPper'

r a ) _{1 4}

c

b) 12

r c ) _{1 0}

. - o 8

7 A MAde electrodes must have a resistance to ground not to uceed

ru'

ohms when used alone c a) 5 c b ) 1 0 { - c ) _{2 5} {- d) 30

t 7 Disregarding all exceptions, the sum of the cross-sectional area of all

r . .

conductors i"-i n:i*ay sh'all not *cied percent of the interior

cross-sectional area of the wireway'

c a) 20 ' b ) _{3 0} r c ) 4 0 r d) 60

t R G i v e n : N i n e ( 9 ) N o . ! A V G . T H H N c o p p e r c o n d u c t o r s i n a c o n d u i t a t 3 0 4 v'

degrees C. Wltat is the maximum atloiitte ampacig in each conductor?

C c r* a

a) 33

'3

b) 38's

c) 40'0

d) ss

t O The minimum total circuit ampacity reeuyl!lo supply an air conditioning

L "

mobr compressor unit which-corro rs 81500 volt amperes of power at a

l i n e v o l t a g e o f 2 l 0 v o l t s i s a m P e r e s . S e l e c t t h e c l o s e s t a n s w e r . f {-. e C (^ C a) b) c) d) 44.3 40.0 35.4 28.3

) n Given: An ollice building .ttas.a required.general tjshtins load of 50'000

- v'

volt amper"i. Tt , general tighting'toad i supptied by a single phase' 230

vo lt feeder circ uitThe minimum calculate d- iurrent in the feeder circ uit

ungroundeo'i*i conductors rs_ amperes. select the closest anEwer'

a) b) c) 208 217 227

o TOTAI RESISTAIICE : TOTAL VOLTAGE

TOTAI A]VTPERES

o Resistance

of n resistors

in parallel is found using the formula:

l/RT = liRl + 1lF.2

+ 1/R3...+1lRn

o Resistance

of two resistor in parallel is found r:sing the product

over the sum formula:

RT= (R1 x R2)/(R1+R2)

o Resistance

of n resistors

in series

is found using the formula:

RT = Rl + R2 + R3 ...+Rn

Using the above

ntles:

Rt: 120 volts i 6 amperes

Rt = 20 ohms

The resistance

of Rl, R2, and R3 in parallel is Rt minus 10 ohms minus 5 ohms

or 5 ohms.

The resistance

of Rl and R2 in parallel

is (10 x 20) / (10 + 20) or 6,7 ohms.

T h e n 5 o h m s = ( 6 . 7

x R 3 ) l( 6 . 7 + R 3 )

5 ( 6 , 7

+ R 3 ) = 6 . 7

x R 3

3 3 . 5 + 5 R 3 = 6 . 7 x R 3

6.7R3 - 5R3=

33.5

R3 (6.7 - 5) = 33.5

R3 = 33.5

I 1.7

R3 = 19.7

ohms

#2 c (18 amperes)

The derating

factor for 9 c1tlrent

carrying

conductors

in a raceway

is 70 percent,

and the ambient derating

factor for 42 degrees

C. is .87. Ampacity of THHN No. 12 is 30

amperes.

,7 x.87 x 30 : L8.27

Elmperes.

Text Reference

section

310-15(b)

table 310-16

and coffection

factors

at bottom of table and Table 3 1 0- 15(bx2)(a)

#3 d (44 amperes)

THW ampacity is 65 amperes.

The ambient

derating

factor is .67 .67 x 65 : 43.55 uunperes

Text Reference

section

3 10-

I 6 and conection

factors

at bottom of table

#4 b (2 inch) The area for 3 -500 kcmil THHN conductors

is 3 x

.7073

-2.1219 For 60 percent

filI using the.8 round offmethod

requires

a 2 inch EMT. Text Reference

section

348-8; Chapter

9,

table 1 notes

4 and 7, Table 4, and Table 5

#5 b (2 inch)

Area of 4 410: 4 x .3197

:1.2788; arca

of No. 3 is

.053

. 1.2788

+ .053

: 1.3318

sq. in. requiring

a2 inch rigid

conduit with a 40 percent

area

of 1.363

sq. in. Text Reference

section

346-7;

Chapter

9 Table I,4,5, and 8

#6 a (accessible)

Conduit

bodies,

junction, pull, and outlet boxes

shall be installed

so that the wiring contained

in them can be

rendered

accessible

Text Reference

section

37 0'29

#7 d (heavy duty) Where connected

to a branch circuit having a

rating in excess

of 20 amperes,

lampholders

shall be of the

healy-duty type. Text Reference

section210-21(a)

#8 b (60) The next larger size permitted by Code is 60 amperes.

Text Reference

sectio

n 240-3(0; 2a0-6(a)

#g b (Il4) Standard

practice

is to keep electrical

equipment

ll4

inch of the surface

in indoor locations

that may become

wet.

#10 a (249) By Table 310-16(bottom)

the derating

factor for 70

degrees

C in the 90 degree

C. column is .58. .58 x 430 A. :249

amperes.

Text Reference

section

310-16 and derating table at

bottom of page

#11 b (50) A fixture that weighs more than 50 lb (22.7 kg) shall be

supported

independent

of the outlet box unless the outlet box is

listed for the weight to be supported.

Text Reference

section

410-16(a)

#l2b (50) A form of general-use

snap switch suitable for use on

either ac or dc circuits for controlling Inductive loads not

exceeding

50 percent

of the ampere

rating of the switch.vw

Text Reference

section

3 80- 17

4(b)(2)

#I3 c (#10) Open individual conductors

shall not be smaller than

the following: For 600 volts, nominal, or less, No. 10 copper or

No. 8 aluminum for spans

up to 50 ft (15.2 m) in length and No. 8

copper or No. 6 aluminum for a longer sPffi, unless supported.

Text Reference

section

225-(a)(l)

#t4 b (insulated

for the ma:<imum

voltage of any conductor

within

the enclosure)

Text Reference

section

300-3(cXl)

# 15 d (8) The conductors

shall not be smaller than No. 8 copper or

No. 6 aluminum or copper-clad

aluminum.

Text Reference

section

230-23

#16 c (25) A single electrode

consisting

_{of a rod, PiPe, or plate that}

does not have a resistance

_{to $ound of 25 ohms or less shall be}

augrnented

by one additional

electrode

of any of the types

specified

in Sections

250-50

or 250'52.

Text Reference

section

250-56

: . , .

'

# I7 a (20) The sum of cross-sectional

areas

of all contained

conductors

at any cross section

of the wireway shall not exceed

20

:

percent

of the interior cross-sectional

area

of the wireway.

. j

#18 b (38.5)

By Table 310-15(bX2)

the derating

factor

for 9

conductors

in ataceway

is 70Yo. .70 x 55 = 38.5 amperes.

!

Text Reference

section

Table

310-16;

Table

310-15(bX2)(a)

'

#Ig a(44.3)

I: plE:8500 VN 240 volts

- 35.4 amperes.

Frorn

u:r

Table 440-32

125 pet cent of 35 .4: 44.3 amperes'

#20 a(208) I - P / E; 50,000

I 240 volts :208 Etmperes.

.

_{Text Reference}

section

Appendix D

Electrician Practice Test 3

a , , i a h i , r m ' r r a r . _{N O . 3}

v u J - 4 l \ u l t u J s l .

I Given: Three (3) 500 kcmit THHN conductors in a raceway at 70 degrees

F-t'o

H/hat is the maximum ollowable current k each conductor if the terminations and equipment is rated at 90 Degtees C?

(-C C (- a) b) c) d)

2. F-texibte cord muy be used in oll of thefollowing locations ucept

--345 3 8 0 430 447 hoists cranes

to replace permanent wiring pendants

Anywhere

Class III, Division 2

Class II, Division I

Unclassified areas at a buik storage plants

r a ) {-

b) r c ) r d )

? Wen a conduit nippte having a maximum lengtft not to exceed 24 inches is

J'

installed, the nippii shall be permined tu beJilled to -percent of its total

cross sectional area

c a ) _{3 0}

c b )

r c )

c d )

4, Drums of gasoline may be stored in what type of outdoor area?

40 50 60 t I

r

f a) b) c) d)

6.

The maximum allowablefiAfor conduit and tubkgfor 3 or more conductors,

not lead covered is

5. The interior of paint spray bootlts ore considered

c a )

r b )

(- c) c d )

Class 1, or Class 2, Division I Class 1, Division 2

Class II, Division I Class II, Division 2

c a ) r b ) r c ) c d )

7.

In a conduit seal, the minimum thickness otthe seoling compound, except

where rced in cables, should in no case be le5,s than

8.

30% 40% 50o/o 60% (- a)

r b )

(' c) 518' r- d) 3/4u

Given: A 30 hpr 3-phase,160 volt, continuous duty induction motor with a

sembefactor of 1.15 and a temperature rise of 40 degrees C. The maximum

rating otthe required separate overload device is_ amperes.

' - a ) r b ) c c ) ll4u l/2" 46 5 0 5 6

o Given: Measurement across a 3-phase squirrel cage motor atfull load are 7o

460 volts and 65 amperes. What should the honepower rating be rcing the Code? c a ) _{3 0} r b) 40 r c) 50 r d) 60

t n Refer to theligure below. Given the circuit shown What is the current in the

L v' neutral conductor? r a ) c b ) . c ) r d ) 25.0amperes 12.5 a.naperes 6.25 amperes 4.2 amperes

u4

U3

u2

a t A J t n

7 7 .

1 ,OOO \A/atts 5oo \A/a.tts N e u t r a l I | 1 2 O v A ( - l l ' l l l ' ' : : = : : : : : : = = : = = = : : : : = : : : : : : : : - '

Given: A 25footfeeder tap. The ampacity of the tap must be at least -tha,t of thefieder conductor or overcunent protectionfrom which il is tapped ( a t^ a) b) c) d)

t ) The normal current allowed on a coyiper bw in an Awiliary Gutters is '- a'

11000 amperes per squsrc inch. The nuntber of amperes which a 2 1/2 x 1/4

inch square copper bus may carry under thse conditions it- amPercs.

c a ) r b) 750 r c) l,'000 c d) t'250

t ? Given: A 240 volt conductor has a total length of 500feet and supplies d z r '

bad of 10 arqperes. The conductor has a resistance of 1.15 ohms per 1'000

feel The total wltage drop in the conductor circuil conducton is percent Select the closest answen

r

_d)

_n

| / The maximumftxture weight that may be supported by the screw sltell of a

'Tc

hmpholder is pornds.

7 5 .

t- _{' 16}

d) r\r

Where a cable is installed through bored holes in woodioists, where

possible, the hoks shall be bored so that the edge of the hole is not less than inch(es) from the nearest edge of the wood member.

r a )

r b )

r c )

J f 7 /- a) c b ) r c ) ) 6 1 0 r a ) c b ) r c ) I

L v 4

L U 2

: - . :

76.

The minimum lighting toad requiredfor the general Eghting (only) of a

church huitding having ou&ide dimensions of 100t by 200' is -

volt-amPefes. c a ) r b ) c c ) r d ) 2,000 4,000 20,000 40,000

r

^) r b ) r c ) r d )

I p Given: A 240 volt, 20 amPere two wire branch circuil If the ,ruEimum

r 'r'

ailowable voltage drop through the circuit conductors is 2,4 volts, what is

the maximum allowable resistance of the circuit conductorc?

t 7 The minimum size copper equipment grounding conductfor grounding r / '

equipmcnt hmting a 10 ampere automatic overcurrent device in the circuit

ahead of the equiPment isNa

6 8 1 0 1 2 r a ) (- b) r c ) c d ) 12 ohms 1 . 2 o h m s .48 ohms .12 ohms

I O The combined load oif two, 230 voltftxzd heaters on a 30 antlrere branch ^ "

circuit shalt not qceed kilowot&, Select the closest dnsreen

(' a) 2.4

r b )

(- c) (^ d)

)n Outlet boxes mounted in combustible walls or ceilings must be mounted so

-v'

that thq will be set back not more than a msimum of -kchfrom the

ftnished surface. ) . ) 5 . 9 24.0 U2

r/4

1 / 8 0 (must be flush)

r

c.

r

C a) b) c) d)

I

Electrician Practice Test 3

. - Q u i z N u m b e r : N o . 3

. _

#1 d (447) the correction

factor at the bottom of Table 310-16

for 70 degrees

F. is 1.04 for 90 degree

rated insulation

such as

I

_{fHHN. 1.04 x 430 amperes}

: 447amperes.

Text Reference

section

Table 310-16

& Temperature

derating

factors

at bottom of table, and section

110-14

#2 c (to replace

pennanent

wiring) Text Reference

section 400-7

,

.,

400-8

#3 d(60) Where conduit or tubing nipples having a maximum

length not to exceed

24 n. (610 mm) are installed

between

boxes,

cabinets,

and similar enclosures,

the nipples shall be pennitted to

"

_{be filled to 60 percent}

_{of their total cross-sectional}

_axea.

Text Reference

section Chaptet

9, Table 1 note 4

#4 d (Unclassified

areas

at a bulk storage

plants.) This permission

-

is given for bulk storage

plants and they are defined in Section

5 1 5- I . Text Reference

section

575-2

#5 a (Class

l, or Class

2, Division 1) The following spaces

shall

'

be considered

Class

I or Class

II, Division I locations,

as

applicable: The interiors of spray booths and rooms.

Text Reference

section

51

6-2(a)

#6b (40%) By Table 1 in Chapter

9,40 percent.

Text Reference

4,

_section

_Chapter

_{9, Table I}

*

#7 c (5/8") In a completed

seal,

1[s minimum thickness

of the

sealing compound

shall not be less than the trade size of the

r

sealinE

fitting ond, in no case,

less than 5/8 in. Text Reference

section

501-5(cX3)

#8 d (60) 125 percent

of 40 is 50 amperes,

but Section 430'34

allows a 140 percent maximum overload.

Text Reference

section

table 430-150;

Sections

430-32(aXl); 430-34

#9 c (50) By Tabl

e 430-150

a 50 horsepower

motor has a fulI load

amperes

of 65. Text Reference

section

430-150

#10 d (4.2 anperes) Cunent through 1000 watt load : L,000/120

-8.3 amperes; Current through 500 watt load : 500/120 = 4.L7

amperes.

8.3 - 4.I -- 4.2 amperes.

Text Reference

section

Basic

Electrical Theory

#11 b (Ll3) Also, the tap conductors

terminate

in a single circuit

breaker or a single set of fuses that will limit the load to the

ampacity of the tap conductors

and shall be protected.

Text

Reference

sectio

n 241 -2l.

(bX2)

#L2b (625)Amperes

: (2.5 x .25) x 1,000: 625 amperes

Text Reference

section

37 4-6(a)

#13 a (3) E:IxR; E:l0 x (500/1,000)xl

.45 : 7 .25 volts;

percent

-(7.251240

_{) x 100}

_{- 3 percent Text Reference}

_section

_Basic

Electrical Theory

#14 b (6) A fixture that weighs more than 6 lb (2.72 kg) or exceeds

16 in. (406 mm) in any dimension

shall not be supported

by the

screw shell of a lampholder.

Text Reference

section

4L0-

15(a)

#15 b (I %) If this requirement

cannot

be met, standard

*nail

plates* can be used. Text Reference

section

300-4(aX1)

#16 c (2000) 100' x 200' - 20,000

sq. ft.,By Table 220-3(a)

1 VA

per square

foot is required

for churches.

1 x 20,000

:20,000 VA.

#17 c (10) By Table 250-122

a40 ampere

OCPD requtues

a No. 10

copper equipment

grounding

conductor.

Text Reference

section

table 250-122

'

#1 8 d (.12 ohms)

R: El I;R: 2.41

20; R - .12 ohms

. The 240

is (2.41240

_{)x 100}

= I percent.

Text Reference

section

review DC

Theory

,

+19 b (5.5)

.8 x 30 :24 €rmperes.

24x230:5520 watts;

'i

5520/1000:

5.5 lcw. Text Reference

section

a2a-3$)

-.''

_{#20 d(0 must be flush) In walls and ceilings constucted of wood}

or other combustible

material,

boxes shall be flush with the

.

_{finished surface}

or project there from Text Reference

section

:

E

Electrician Practice Test 4

1. Refer to theJigure below. What is wrong with the grounding rod illwtrated?

r

a) It is not 10 feet long.

(-

b) It requires a gror.urd ciamp

r

c) It is not 30 inches deep

f

d) There is nothing wrong, according to the Code

-J

Service

Grounding

Electrode

Conductor

S o i l

t

2 f t . d e e p

I

) Which of thefollowing is not a standardfnse or inverse time chcuit breaker a' size? r a ) . . c ) c d) 55

? fn general, a continuous dttty motor rated at more than I horsepower shall be

"'

protected by a sqarate overload daice rated at no more than - percent

of the motor nancplatefull-load current rating.

3 5 45 50 r a ) r b ) r c ) r d) 125

,t Where direct buried conductors or cab:les emergefrom the ground they shall

ac

be protected by enclosures or raceways. In no case shall the protection be

required to uceed - inches belowJinished grade

r a ) r b ) r c ) r d )

{ Given: Three resistorc (R1, H, and R3) are instuAed in a series circuit The

v'

power used by.R/ ts 100 watts and the power used by M is 75 watts. The total power used by the circuit is 225 wat6. Then the power used by resbtor RJ it

r4tatts,

r

r

a

(-a) b) c) d) 1 0 0 1 1 5 l 2 l 8 24 3 0 24 5 0 175

Refer to thefigure below. The total rcsbtance Rt is

closest answen

ohms. Sekct the

6.

c a ) r b ) r c ) r d ) r a ) . . b ) c c ) (- d) 9.4 1 0 . 5

grognded by running a ground from the range frame to the outlet

box, wrapping the ground around the cord and then grounding it

to the outlet box. ungrounded

grounded by a 4-wire cord containing the two hot leads, the

neutral, and a green grounding conductor. (the range requires a

4-wire cord)

grounded at the range by bonding the grounded conductor to the

ftrnge frarne.

1 5 40

7 Given: Afree standing electric range b rated n0n40 volts and requires a

r t

neutral connectionfor the 120 vott timer and lights. The range is equipped witlt 3 wire cord with No. 8 copper condaclors ond a 3 prone plugfor two hot

leads and neutraL The rangeframe shall be permitted to be -'

PE

15 ohrns

9.

The Code requires at least two stnall appliance branch circuibfor

dwellings, These small appliance circuib shall be assigned a load of volt-amperes each when calculatingfeeden and service entrance

requiremen&. r a ) r b ) c c ) f* d) I0. T:"*^*{*efollowing

receptacles may be connected to the small appliance

| | A metal underground water pipe in direct contact with the earth for at least

1 1'

il feet has traditionally be:en a preferred groanding electrode For all new

construction, a metal underground waler pipe is -.

r a ) . - b ) (- c) c a ) r b ) . ^ c ) (- d) 750 1000 I 500 2000

receptacles for electric clocks in the kitchen

garage ceiling receptacles for garage door openers

hallway which are close to the kitchen

still the preferred grounding electrode, by itself, when

available.

still an acceptable grounding elechode, but it must be

supplemented by at least one additional grounding electrode.

no longer accepted as a grounding elechode

accepted as the only grounding electrode when buried at least

three(3) feet below the surface.

t 2 Thermal insulation shall not be installed within inches of a recessed

L -'

figMfirture enclosure unless the recessed ligfutirture is identiJied as

suitablefor dbect contact with insulatiort

c ^) (- b) r c ) r d ) 2 4 5

I

:

t ? The No. 12 or 11 grounded conductor of a bronch circuit shall be identifrcd

t J a

Dv a w,re.

white or gxay color or three continuous white stripes on other

a) _{than green insulation}

t I The Code deJines ttcontinuous loadtt as o load where the maximum current

z "

is upected to continuefor at least -,

c b )

r

c)

r d )

green color or bare copper

yellow color black color

r a )

r b )

l- c) r d )

one hour or more two hours or more tfuee hours or more twenty four hours a daY

c a ) r b )

i .

c) ' d )

76.

Outlet boxes mounted in non<ombustible walls or ceilings must be

mounted so that they will be set back not morc than a moximum of inch trom th e Jin is hed s urface.

t < For calculating the me,imum nwnber of conduclors allowed in an outlet t '"

box the volume requiredfor each No. 12 conductor it- cubic inches.

I

r

a) b) c) 2 2.25 2 . 5 3 1/8 1 t 4

u2

t Z Screr*shell lamphoWers shall be wired so thgt ttle '' ' '

connected to the scret+t-shell

condtrctor is c a )

r b )

r c )

' - d ) grounding grounded ungrounded bare 1 / 8 Ll4 3 t 8 il2 outside dimensions of inside dimensions of heigbt of number of rooms in

7 8 .

Enclosuresfor overcurrent devices in damp or wet locations shall be

mauinUd so there is at least - inch alr space between the wall or other

support surface. r a )

c b ) c c ) r d )

, A Are least _inches offree conductor shall be left at each outlet and

" '

switch pointfor splices orfor the connection ofJirtures or devices.

r a ) ₅ r b) 6 ' c ) ₇ r d) 8

20. In determini?8.!o-:d o1th.1,volt'aTlere Pe: squarefoot basis the

the building shall be usedfor eachfloor.

('

r

r

a

a) b) c) d)

Electrician Practice Test 4

AIISWERTS

#1 c (it is not 30" deep) Where rock bottom is encountered,

the

electrode

shall be driven at an oblique angle not to exceed

45

degrees

from the vertical or shall be buried in a trench that is at

least 2%ft(762 mm) deep.

Text Reference

section250'52(c)

See Diagram

Grounding Electrode Conductor

a ft. tong by 1/2 inch diameter solid copper rod

#2 d (55) 50 amperes and 60 amperes

are standard

fuse and

circuit breaker sizes but 5 5 is not. Text Reference

Section

240-6(a)

#3 d (125)

Text Reference

Section

430-32(aXl)

#4b (18) Direct-buried

conductors

and cables

emerging

from the

glound shall be protected

by to a point at least

8 ft above

finished

#5 b (50) 225 -75 - 100:50 watts

TextReference

SectionBasic

Electrical

Theory

#6 a (9.4) Basic electrical

theory. Rt - (Rl x R2)/ (Rl + R2); RT

: (25 x 15) I (25 +15) : 9.4 ohrns

Text Reference

Section

Basic

Electrical Theory:

Product

over the sum.

#7 c (grounded

by a 4-wire cord containing

the two hot leads,

the

neutral, and a green grounding conductor.

the range requires a

4-wire cord) A new change

no longer allows ranges

to be grounded

with he grounded

conductor

in new installations.

Text Reference

Section 250-142

#8 b (two (2) single pole circuit breakers,

tied together)

In dwelling

units, a multiwire branch circuit supplying more than one device or

equipment on the same

yoke shall be provided with a means

to

disconnect simultaneously

all ungrounded

conductors

at the

panelboard

_{where the branch circuit originated.}

Text Reference

Section 210-4(b)

#9 c ( 1 500) Text Reference

Secti

on 250-142

# 10 a (receptacles

for electric clocks in the kitchen)

Also the small appliance

branch circuits can supply Receptacles

installed to provide power for supplemental

equipment

and lighting

on gas-fired ranges,

ovens,

or counter-mounted

cooking units. Text

Reference

_{Section2l0-52(bx2)}

Exception

No. 1

R2

1 5 o h m s

# 1 1 b (still an acceptable

gounding electrode,

but it must be

supplemented

by at least one additional

glounding elecfrode.)

Because

plumbers

keep replacing

metal pipe with plastic pipe the

metal underground

water pipe is no longer a reliable underglound

grounding electrode.

Text Reference

Section

250-50(a)

#12 b (3) Thermal

insulation

shall not be installed

above

a recessed

fixture or within 3 in. (76 mm) of the recessed

fixhre*s enclosure,

wiring comparfment,

or ballast unless it is identified for contact

with insulation,

Tnrc IC. Text Reference

Section

410-66(b)

#13 a(white or glay color or three continuous

white stripes

on

other tlan green insulation.)

Ax insulated

grounded

conductor

of

No. 6 or smaller shall be identified by a continuous

white or

natural g;ay outer frrish or by three continuous

white stripes on

other than green insulation

along its entire length. Text Reference

Section

200-6

#14 c (three hours or more) Continuous

Load: A load where the

maximum culrent is expected

to continue

for 3 hours or more'

Text Reference

Section

Article 100

#15 b (2.25)No.

2 requires

2.25 cubic inches

per Table370-16(b)

Text Reference

Section

Table 370-16(b)

# 1 6 b (I I 4") Text Reference

S ectio

n 37 0-20

#17 b (grounded)

For devices

with screw shells,

the terminal

for

ttre gfo*ded conductor

shall be the one connected

to the

# 1 9 b ( 6 ) t l e a s t 6 i n . ( | 5 2 m m ) o f f r e e c o n d u c t o r ' m e a S u r e d f r o m

the point in the box where it emerges

from its raceway or

cable sheath,

shall be left at each outlet junction, ffid switch

point for splices or the connection

of fixtures or devices.

Text Reference

Section

300-14

I

# 2 0 a ( o u t s i d e d i m e n s i o n s o 0 T h e f l o o r a r e a f o r e a c h f l o o r s h a l l b e

computed from the outside dimensions of the building,

dwelling unit, or other area involved. Text Reference

Section

220-3(b)

Electrician Practice Test 5

7 The circuit conductor that is defined os being intentionally grounded is the

1' conductor. r a) grounding ' b) grounded r c) equiPment grounding r d) grounding electrode

2. Class II location are those that are hazardous because of the presence of

a) ignitable vaPors r u; iPitaule fibers c c) combustible dust r d; combr:stible liquids

2 ff tbee resistorc with values 5, 10, and 15 ohms respectively are connected in

Jc

iaraltet, tlrc combined total resbtance b- ohms. Select the closest

answef, c a ) o ' 4 r b) 2'3 c c) 2'7

r

_{d) 3o'o}

/ The wiring in a 200foot long branch circuil measures a total resistance of zo

0.5 ohms. What is the resistance per 1,000feet?

r a) 0'5 ohms r b) 1'o ohms -' C) l'') OnmS ,- 5.0 ohms ' d )