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2011 NEC Review PracticeTest 1

Course Name: 2011 NEC Review
Quiz Number:  No. 1
Teacher:  Gerald Newton
Teacher's Home Page:  http://www.electrician2.com
Teacher's Email:  electrician@electrician2.com

No. of Questions= 20



1In Class 1, Division 1 locations, conduit seals shall be placed a maximum of ______inches from an enclosures containing arc producing equipment. 


            

a)12

b)18

c)24

d)30






2What length is required for the pullbox in the diagram below? The box is used with 480 volt conductors that are not spliced.


            

a)32 inches

b)24 inches

c)48 inches

d)any length





3What is the load that can be used for the service calculation for a dwelling unit when the Range has a nameplate rating of 13 KW?


            

a)13 kw

b)8.4 kw

c)8 kw

d)none of the above






4What size copper equipment grounding conductor is required for a circuit protected with a 50 ampere circuit breaker?


            

a)No. 12 copper

b)No. 10 copper

c)No. 8 copper






5What is the highest voltage permitted for a Class 1 power limited circuit?


            

a)1,000 volts

b)30 volts

c)24 volts

d)None of the above






6What is the missing voltage in the sketch below?


            

a)120 volts

b)120 volt's

c)1200 volts

d)12,000 volts





7What is the minimum size 10 feet long Rigid Metal conduit required for the following 9 conductors? 4 THWN #12 CU, 2 RHW (covered) #8 CU, 3 RHW (covered) #6 CU


       

a)1 1/2 inch

b) 2 inch

c) 1 1/4 inch

d)None of the above






8What is the efficiency of a motor which draws 4.5 kilowatts from the line and delivers 5 horsepower?


              

a)80 percent

b)83 percent

c)90 percent






9Power Factor can be defined as:


      

a)True Power divided by Apparent Power

b)Apparent Power divided by True Power

c)Apparent Power divided by volts x amperes






10What is the power factor for a three phase system operating when the wattmeter reads 6,000 watts, the voltmeter reads 208 volts, and the ammeter reads 20 amperes?


            

a).90 or 90 percent

b)1.04 or 104 percent

c).83 or 83 percent






11What is the power factor for a 8000 watt load connected to a 240 volt AC single-phase circuit if the current is 36 amperes?


            

a).8 or 80 percent

b).93 or 93 percent

c)1.0 or 100 percent






12For the figure below if No. 4 or larger conductors are installed in the raceways dimension X shall be ____inches minimum. The box is used for splices and doe not have the cubic inch dimensions marked on it.


            

a)18 inches

b)16 inches

c)24 inches





13For the 4-way Switch, which is the correct hookup?




a)D to T, E to R, F to T, G to S

b)D to S, E to R, F to T, G to W

c)D to R, E to T, F to S, G to W





14
A dwelling has a floor area of 2200 sq. ft., exclusive of an unfinished 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. Assume range and dryer kW ratings equivalent to kVA ratings in accordance with Sections 220-18 and 220-19.Computed Load [see Section 220-10] 
  
Fill in the following information:
 
General Lighting Load: _____ sq. ft. at __ VA per sq. ft. =_______ VA Minimum 
 
Number of Branch Circuits Required:
General Lighting Load: ______ VA / 120 V = ___ A
General Lighting Load: ______ VA / 120 V = ___ A
           This requires______ 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 Lighting _______ VA
           Small Appliance ______ VA
           Laundry ______ VA
           Total 11100 VA
          ______ VA at 100% 3000 VA
           _______ VA - 3000 VA =______ VA at _____% is ______ VA
           Net Load _______ VA
           Range  ______ VA
           Dryer________ VA
           Net Computed Load _______ VA
           Net Computed Load for 120/240-V, 3-wire, single-phase service or feeder
          ________ VA / 240 V = ______ A
           Net computed load exceeds 10 kVA.  Would require service 
           conductors to be  _____ A.
Calculation for Neutral for Feeder and Service:
           Lighting and Small Appliance Net Load _____ VA

           Range: _____ VA at 70%  is 5600 VA
           Dryer : _______ VA at 70%  is ______ VA
           Total ________ VA

Computed Load for Neutral:
  __________ VA / 240 V = ______ A
 

What is the final computed load for the neutral in the above load calculation?



       

a)65.9

b)63.7

c)100

d)111






15The correct hookup for the 3-way switch below is:


     

a)A to X, B to Z, C to Y

b)A to Y, B to X, C to Z

c)A to Z, B to Y, C to X

d)A to Z, B to X, C to Y





16Connect the delta wound 480 volt motor leads for the high voltage windings in the diagram below.


            

a)9-7, 4-6, 8-9, 5-4

b)4-7, 5-8, 6-9

c)4-9, 6-8, 5-7





17Find the correct size ventilated cable tray for the diagram below.


             

a)6 inches

b)12 inches

c)18 inches

d)24 inches





18Find the voltage across the 5 ampere load after the neutral is opened. Both loads are resistive and the power factor is 1.0.


            

a)180 volts

b)120 volts

c)0 volts





19Find the size of inverse time circuit breaker required for the feeder protecting the following polyphase induction motors. These motors are Design B and have a Service Factor of 1.15 and are individually protected with inverse time circuit breakers.


               

a)150 ampere

b)175 ampere

c)200 ampere





20How many cubic inches is required for the following box? All conductors are No. 14 and there are no internal clamps.


                

a)12 cubic inches

b)16 cubic inches

c)18 cubic inches

d)20 cubic inches










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© 2008 Gerald Newton