NEC Wiring Methods and Materials 4

Question 1

What box fill volume allowance does Table 314.16(B) assign to each 12 AWG conductor?

Accepted Answer

2.25 cubic inches

Answer

Table 314.16(B) assigns 2.25 cubic inches per 12 AWG conductor.

Question 2

In a box fill calculation, how is a single-gang receptacle on a yoke counted?

Accepted Answer

As two volume allowances based on the largest conductor connected to it

Answer

NEC 314.16(B)(4) counts each yoke or strap as a double volume allowance based on the largest conductor connected to the device.

Question 3

A box contains four equipment grounding conductors. How many volume allowances do they add to the box fill calculation?

Accepted Answer

One, based on the largest EGC

Answer

NEC 314.16(B)(5) counts all equipment grounding conductors together as a single volume allowance based on the largest one.

Question 4

Listed flexible metal conduit (FMC) with listed fittings can serve as the equipment grounding conductor only if the total length in the ground return path does not exceed what?

Accepted Answer

6 feet

Answer

NEC 250.118 allows FMC as an EGC only when the circuit is protected at 20 A or less and the combined length is no more than 6 ft.

Question 5

Flexible metal conduit must generally be supported at intervals not exceeding what distance?

Accepted Answer

4.5 feet

Answer

NEC 348.30 requires FMC to be supported every 4.5 ft and within 12 in of each box or termination.

NEC Practice Test

NEC Practice Test

NEC Wiring Methods and Materials 4