Journeyman Electrician Practice Test 17

Question 1: What grounding electrode must be used for a separately derived system (transformer) inside a building?

• The nearest metal water pipe at any point
• The structural steel only
• A new ground rod at the transformer
• The building grounding electrode system

NEC Reference: NEC 250.30(A)(4)

Question 2: How must the top of a driven ground rod be installed?

• Flush with or below grade, unless protected
• Anywhere, if a listed clamp is used on it
• At least 12 in. above finished grade
• Exactly 6 in. above grade for inspection

NEC Reference: NEC 250.53(A)(4)

Question 3: A service has three parallel sets of 500 kcmil copper, each set in its own raceway, with an individual supply-side bonding jumper for each raceway. What size copper jumper is required for each raceway?

• 250 kcmil
• 3/0 AWG
• 1/0 AWG
• 2 AWG

NEC Reference: NEC 250.102(C)(2)

Question 4: A 10 ft feeder tap of 6 AWG copper is taken from a feeder protected at 400 A. What is the minimum copper EGC for the tap?

• 10 AWG
• 8 AWG
• 6 AWG
• 3 AWG

NEC Reference: NEC 250.122(G)

Question 5: Why are electrical systems connected to earth (grounded)?

• To reduce harmonic currents in the neutral
• To carry normal load current back to the source
• To trip breakers on overloads in the circuit
• To limit voltage from lightning, surges or high-voltage contact

NEC Reference: NEC 250.4(A)(1)

Question 6: A mobile home park feeder supplies 8 mobile home lots, each calculated at the 16,000 VA minimum. What is the feeder demand load?

• 128,000 VA
• 56,320 VA
• 44,800 VA
• 35,840 VA

NEC Reference: NEC 550.31 and Table 550.31

Question 7: A 480-volt, 3-phase feeder carries 150 A for 250 ft on 1/0 AWG copper (105,600 cmil, K = 12.9). What is the voltage drop as a percentage?

• 0.8%
• 1.7%
• 3.3%
• 4.1%

NEC Reference: NEC Chapter 9, Table 8

Question 8: Three 100-watt lamps operate for 10 hours. How much energy do they use?

• 0.3 kWh
• 1 kWh
• 3 kWh
• 30 kWh

Question 9: Under the 2023 NEC, which 125-volt, 15- and 20-ampere receptacles in a dwelling kitchen require GFCI protection?

• All kitchen receptacles
• Only those serving the countertop
• Only those on the island
• Only those within 6 ft of the sink

NEC Reference: NEC 210.8(A)(6)

Question 10: A receptacle serving a dwelling kitchen countertop must be located on or above the countertop, but not more than how far above it?

• 24 in.
• 20 in.
• 18 in.
• 12 in.

NEC Reference: NEC 210.52(C)

Question 11: A service mast supports the overhead service-drop conductors. What else may be attached to the mast?

• Cable TV and telephone drops for the same building
• A satellite dish if it is under 1 m across
• A flag pole bracket if it is bolted to the mast
• Only power service-drop conductors

NEC Reference: NEC 230.28(B)

Question 12: The voltage rating of electrical equipment must be:

• Not less than the circuit's nominal voltage
• Exactly equal to 120 V for all branch circuits
• At least twice the circuit voltage for safety
• Lower than the circuit voltage to limit stress

NEC Reference: NEC 110.4

Question 13: Under the Article 100 definition, how is a panelboard accessed?

• From the front only
• From the top only
• From the front and rear
• From the rear only

NEC Reference: NEC Article 100

Question 14: A 3-phase, 4-wire wye system has 347 V from each phase to neutral. What is the line-to-line voltage?

• 480 V
• 600 V
• 694 V
• 1,041 V

Question 15: A circuit uses two phase conductors and the neutral of a 208Y/120-volt, 4-wire wye system. For ampacity adjustment, how is the neutral counted?

• It is never counted in a wye-connected system
• It counts only if it is larger than 10 AWG
• It counts as half a conductor for adjustment
• It is counted as current-carrying

NEC Reference: NEC 310.15(E)(2)

Question 16: Type AC cable may be left unsupported at terminals where flexibility is necessary, for a length not exceeding:

• 6 ft
• 4½ ft
• 2 ft
• 12 in.

NEC Reference: NEC 320.30(D)

Question 17: A single conductor of an AC circuit passes alone through a steel box wall. What does 300.20(B) permit to reduce inductive heating?

• Increasing the conductor one size to carry the extra heat
• Cutting slots in the metal between the holes
• Wrapping the conductor with two layers of electrical tape
• Painting the inside of the box with insulating paint

NEC Reference: NEC 300.20(B)

Question 18: Where must overcurrent devices be located?

• Where not exposed to physical damage
• Only outdoors in raintight enclosures
• Only in locked electrical rooms or vaults
• At least 10 ft above the finished floor

NEC Reference: NEC 240.24(C)

Question 19: A panelboard uses a series-combination rating (a main fuse protecting lower-rated branch breakers). How must the equipment be marked?

• Marked with the utility name and account number
• Marked only on the engineer's single-line drawings
• No marking is required if the inspector approves
• Field marked as a series combination system

NEC Reference: NEC 110.22(C)

Question 20: A motor with a 40 A full-load current will not start on a 100 A inverse time breaker (250%). What is the maximum the breaker may be increased to?

• 125 A
• 150 A
• 175 A
• 200 A

NEC Reference: NEC 430.52(C)(1) Exception No. 2

Question 21: What is the minimum size copper branch-circuit conductor (60 °C terminals) for a 2 hp, 115-volt, single-phase motor?

• 14 AWG
• 12 AWG
• 10 AWG
• 8 AWG

NEC Reference: NEC 430.22 and Table 430.248

Question 22: For a one-family dwelling, what is the maximum PV system DC circuit voltage permitted?

• 120 V
• 300 V
• 600 V
• 1,000 V

NEC Reference: NEC 690.7

Question 23: A commercial building has an optional standby generator. What sign is required at the service-entrance equipment?

• No sign is required for optional standby systems
• A list of every load connected to the standby system
• Type and location of each standby source
• The generator fuel level and run-time remaining

NEC Reference: NEC 702.7(A)

Question 24: Each critical care (Category 1) patient bed location must have at least how many receptacles?

• 6
• 8
• 10
• 14

NEC Reference: NEC 517.19(B)

Question 25: For temporary power during construction, how may Type NM cable be used?

• NM cable is never allowed for temporary wiring
• Only in one-family dwellings up to three floors
• Only concealed inside walls, floors or ceilings
• Any building, no height limit, not concealed

NEC Reference: NEC 590.4(B) and (C)

Question 26: For a cord-and-plug-connected appliance, what may serve as the disconnecting means?

• An accessible plug and receptacle
• Only a separate switch within sight of the appliance
• The appliance thermostat set to the off position
• Only the branch-circuit breaker in the panelboard

NEC Reference: NEC 422.33(A)

Question 27: In an office building, fluorescent luminaires with double-ended lamps and ballasts that can be serviced in place must have:

• A dedicated branch circuit for each luminaire
• A lockable switch at the panelboard only
• A disconnect, internal or external to each
• A GFCI device on each individual luminaire

NEC Reference: NEC 410.130(G)(1)

Question 28: A U-pull box has two 2½ in. conduits entering the same wall. What is the minimum distance from that wall to the opposite wall?

• 15 in.
• 17.5 in.
• 20 in.
• 30 in.

NEC Reference: NEC 314.28(A)(2)

Question 29: Electrical metallic tubing (EMT) is NOT permitted:

• In dry locations above suspended ceilings
• Where subject to severe physical damage
• In concealed work inside framed walls
• In damp locations such as covered porches

NEC Reference: NEC 358.12

Question 30: A transformer has four times as many turns on its secondary winding as on its primary. With 120 V applied to the primary, what is the secondary voltage (ignoring losses)?

• 480 V
• 240 V
• 120 V
• 30 V