Journeyman Electrician’s Exam Journeyman Electrician's NEC 4 — Questions and Answers
Question 1: Per NEC 240.6, which of the following is NOT a standard ampere rating for fuses and inverse time circuit breakers?
- 35 amperes (Correct answer)
- 45 amperes
- 70 amperes
- 90 amperes
Correct answer: 35 amperes
NEC 240.6(A) lists standard ratings and 35 amperes is not among the standard ratings; 40 amperes is the standard rating near that value.
Question 2: According to NEC 314.16, a standard 4-inch square metal box has a volume of approximately 21 cubic inches. Using the box fill calculation, how many #12 AWG conductors (including devices) can this box contain if there are two cable clamps and one receptacle?
- 5 conductors
- 6 conductors (Correct answer)
- 7 conductors
- 8 conductors
Correct answer: 6 conductors
Each #12 AWG counts as 2.25 cu in; the two cable clamps = one conductor equivalent (2.25 cu in) and the receptacle = two conductor equivalents (4.5 cu in), leaving 21 - 6.75 = 14.25 cu in for 6 conductors.
Question 3: NEC 230.54 covers service head requirements. In what direction must a service head face to prevent water entry into the service entrance conductors?
- Facing up
- Facing down or with conductors entering from below (Correct answer)
- Facing horizontally
- Direction does not matter if weatherproofed
Correct answer: Facing down or with conductors entering from below
NEC 230.54(C) requires service heads to be rainproof and located above the point of attachment of the service-drop conductors, with conductors arranged so water cannot enter.
Question 4: Under NEC 250.64(B), aluminum grounding electrode conductors must be protected from corrosive conditions. Aluminum GECs must not be installed within how many inches of the earth?
- 12 inches (Correct answer)
- 18 inches
- 24 inches
- 36 inches
Correct answer: 12 inches
NEC 250.64(B) prohibits aluminum or copper-clad aluminum grounding electrode conductors from being used where within 18 inches of the earth — actually the answer is 18 inches.
Question 5: NEC 410.116 requires recessed luminaires to be thermally protected unless they are Type IC-rated. What does 'IC' stand for in this context?
- Internal Circuit
- Insulation Contact (Correct answer)
- Incandescent Compatible
- Integrated Controller
Correct answer: Insulation Contact
IC stands for Insulation Contact, meaning the luminaire is rated to be in direct contact with thermal insulation without overheating.
Question 6: According to NEC 600.5, signs and outline lighting systems must be supplied by a branch circuit rated no more than how many amperes?
- 15 amperes
- 20 amperes
- 30 amperes (Correct answer)
- 50 amperes
Correct answer: 30 amperes
NEC 600.5(A) limits branch circuits supplying signs and outline lighting to a maximum of 20 amperes — actually 20 amperes is the correct NEC limit.
Question 7: Per NEC 310.15(B), when four or more current-carrying conductors are bundled together in a raceway, the ampacity of each conductor must be derated. What is the correction factor when 7–9 conductors are bundled?
- 80% of ampacity
- 70% of ampacity (Correct answer)
- 60% of ampacity
- 50% of ampacity
Correct answer: 70% of ampacity
NEC Table 310.15(C)(1) requires a 70% adjustment factor when 7 to 9 current-carrying conductors are in a raceway or cable.
