Journeyman Electrician Practice Test 19

Question 1: If the total ampere of house is 30 which has three branch circuits, what is the minimum size of a branch circuit wire that can be used?

• No 6
• No 8
• No 10

Question 2: The distance between service pole and the house building is 120 ft. what is the minimum overhead span wire size?

• No 6
• No 8
• No 10

NEC Reference: NEC 225.6(A)

Question 3: The emergency power supply in hospital should provide full power within ............. sec of normal power failure.

• 10
• 30
• 50
• 60

Question 4: If the battery bank is used as emergency supply, the battery must be of size that will supply the load for a minimum of  .......... hours

• 1 1/2
• 1
• 2
• 1/2

Question 5: The equivalent of  86 ⁰F in degree centigrade is ......................... ⁰ C.

• 30
• 212
• 97
• 47

Question 6: If five mobile homes are connected to one feeder with an assumed load of 16000 watts each, at 115/230 volts, what is the minimum ampacity of the wires in a feeder circuit?

• 115 amperes
• 348 amperes
• 174 amperes
• 195 amperes

Question 7: what is the power required for lighting the 800 sq ft apartment?

• 800 watts
• 2400 watts
• 1600 watts

Question 8: A disconnect switch must be within sight of the motor it controls. What does "within sight" mean in the NEC?

• 10
• 25
• 47.5
• 50

Question 9: Which of the following electrical switching device is utilized to isolate a circuit or equipment from the power supply?

• circuit breaker
• protection device
• disconnection switch
• fuse

Question 10: ................................... is the integral part of the motor which protects the motor from over heating.

• Internal fuse
• Ground fault protector
• thermal protector
• over load protector

Question 11: When sizing motor branch-circuit conductors, what current value must be used according to NEC 430.6(A)(1)?

• The current from the motor nameplate
• The current from NEC Table 430.247 through 430.250
• Any value the electrician chooses that seems safe
• The locked-rotor current from the motor nameplate

NEC Reference: NEC 430.6(A)(1)

Question 12: What is the minimum ampacity of a branch-circuit conductor supplying a single motor?

• 100% of the motor full-load current
• 115% of the motor full-load current
• 125% of the motor full-load current
• 150% of the motor full-load current

NEC Reference: NEC 430.22

Question 13: Motor overload protection (overload relay) is designed to protect .............

• The overcurrent protective device (fuse or breaker) only
• The motor and motor branch-circuit conductors from overheating
• The building wiring from short circuits
• The power supply transformer only

NEC Reference: NEC 430.32

Question 14: When installing 3 or more conductors in a conduit, what is the maximum percent conduit fill allowed?

• 25%
• 31%
• 40%
• 53%

Question 15: When calculating box fill per NEC 314.16, each equipment grounding conductor (EGC) counts as .............

• Zero — EGCs are never counted in box fill
• One conductor for each EGC entering the box
• All EGCs combined count as only one conductor
• Two conductors for each EGC

NEC Reference: NEC 314.16(B)(5)

Question 16: How is an isolated ground receptacle identified?

• Blue colored body
• Red colored body
• Orange colored body or orange triangle on the face
• Yellow colored body

Question 17: How many service disconnecting means can be installed for a single service?

• Two
• Four
• Six
• Ten

NEC Reference: NEC 230.71(A)

Question 18: Service-entrance conductors that pass through the exterior of a building and are exposed to physical damage must be .............

• Installed underground even on exterior walls
• Protected by rigid metal conduit, IMC, EMT, or other approved means
• Painted with weather-resistant paint only
• No protection is needed — service conductors are always large enough

NEC Reference: NEC 230.50(A)

Question 19: A new 240-volt, 30-ampere clothes dryer circuit requires how many conductors total?

• 2 conductors (2 hots only)
• 3 conductors (2 hots + 1 neutral)
• 4 conductors (2 hots + 1 neutral + 1 ground)
• 5 conductors (3 hots + 1 neutral + 1 ground)

NEC Reference: NEC 250.140

Question 20: How does NEC Article 100 define a "continuous load"?

• A load that runs for more than 1 hour
• A load that runs for more than 2 hours
• A load where maximum current continues for 3 hours or more
• Any load that is turned on 24 hours a day

NEC Reference: NEC 100

Question 21: A branch circuit supplying a continuous load must be sized so the load does not exceed what percentage of the breaker rating?

• 70%
• 80%
• 90%
• 100% — breaker can run at full rated current

NEC Reference: NEC 210.20(A)

Question 22: Power factor is defined as the ratio of .............

• Reactive power to apparent power
• True power (watts) to apparent power (volt-amperes)
• Voltage to current
• Watts to kilowatts

Question 23: The unit of measurement for reactive power is .............

• Watts (W)
• Volt-amperes (VA)
• Volt-amperes reactive (VAR)
• Kilowatts (kW)

Question 24: Where in the NEC do you find conductor ampacity tables for copper and aluminum conductors?

• NEC Chapter 9, Table 1
• NEC Article 310 (Table 310.12)
• NEC Article 240
• NEC Article 220

NEC Reference: NEC 310.12

Question 25: For the same wire gauge, which conductor has the higher ampacity?

• Aluminum has higher ampacity
• Copper has higher ampacity
• Both have the same ampacity
• It depends on the temperature rating only

Question 26: What is the recommended maximum voltage drop for a branch circuit under normal conditions?

• 1%
• 3%
• 5%
• 10%

Question 27: In a balanced 3-phase, 4-wire wye system, the neutral wire carries .............

• The sum of all three phase currents
• Zero current when the system is perfectly balanced
• Full load current at all times
• Only harmonic currents

Question 28: What formula is used to calculate the true power (watts) in a 3-phase system?

• P = VL × IL × PF
• P = 3 × VL × IL × PF
• P = √3 × VL × IL × PF
• P = VL² ÷ R

Question 29: The locked-rotor current (LRC) of a motor is typically how many times the full-load current?

• 1 to 2 times the full-load current
• 2 to 3 times the full-load current
• 6 to 8 times the full-load current
• 10 to 12 times the full-load current

Question 30: What does the kVA rating on a transformer nameplate represent?

• The maximum kilowatts the transformer can output
• The maximum apparent power the transformer can supply continuously
• The no-load voltage of the transformer
• The transformer efficiency at full load