E2 NEC Compliance 3

Question 1

NEC 310.15(B) permits ambient temperature correction factors to be applied to conductor ampacity. What reference temperature is used for conductors rated 60°C through 90°C in standard NEC tables?

Accepted Answer

30°C

Answer

25°C

Answer

40°C

Answer

60°C

Question 2

Under NEC 408.36, panelboards used as service equipment in commercial occupancies must be rated for use as service equipment, which requires what additional protection?

Accepted Answer

A main overcurrent protective device or multiple main breakers not exceeding 6

Answer

GFCI on all circuits

Answer

A separate disconnect outside the panel

Answer

Surge protection on the feeder

Question 3

NEC 285.25 requires Type 1 SPDs installed on 120/240V single-phase services to be connected to which conductors?

Accepted Answer

Each ungrounded conductor and the neutral

Answer

Each ungrounded conductor and the equipment grounding conductor

Answer

The neutral and grounding electrode conductor only

Answer

Line-to-line across the two ungrounded conductors only

Question 4

What does NEC 230.95 require on solidly grounded wye services of more than 150 volts to ground but not exceeding 600 volts phase-to-phase?

Accepted Answer

Ground-fault protection of equipment (GFPE)

Answer

AFCI protection

Answer

Differential relaying

Answer

Double-ended switching

Question 5

Per NEC 314.28(A)(1), straight pulls in pull boxes require the box length to be at least how many times the trade size of the largest raceway?

Accepted Answer

8 times

Answer

4 times

Answer

6 times

Answer

12 times

Question 6

NEC 501.15 governs conduit seals in Class I hazardous locations. Where must seals be installed relative to the boundary of the hazardous area?

Accepted Answer

Within 18 inches of the hazardous area boundary

Answer

Within 36 inches of the enclosure

Answer

Within 18 inches of the enclosure or the boundary, whichever is less

Answer

At every junction box within the hazardous area

Question 7

According to NEC 250.66, the minimum size of the grounding electrode conductor for a service using 350 kcmil copper service conductors is:

Accepted Answer

2 AWG copper

Answer

4 AWG copper

Answer

1/0 AWG copper

Answer

3/0 AWG copper