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

The NEC ampacity tables are based on a 30°C (86°F) ambient temperature; correction factors must be applied for other ambient conditions.

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

NEC 408.36 requires panelboards used as service equipment to have a main overcurrent device or not more than six circuit breakers to serve as the main disconnect.

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

Type 1 SPDs must connect between each ungrounded conductor and the neutral to provide proper surge protection across all legs.

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

NEC 230.95 mandates ground-fault protection of equipment for solidly grounded wye services over 150V to ground to prevent equipment damage from arcing ground faults.

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

For straight pulls, NEC 314.28(A)(1) requires the box length to be at least eight times the trade size of the largest raceway entering the box.

(E2) E2 Commercial Electrical Inspector Practice Test

(E2) E2 Commercial Electrical Inspector Practice Test

E2 NEC Compliance 3