Journeyman Electrician’s Exam Journeyman Electrician's Boxes and Enclosures

Question 1

According to NEC Table 314.16(B), what is the volume allowance assigned to each 14 AWG conductor for box fill calculations?

Accepted Answer

2.00 cubic inches

Answer

NEC Table 314.16(B) assigns a volume allowance of 2.00 cubic inches for each 14 AWG conductor in box fill calculations.

Question 2

Per NEC 314.16(B)(4), how does a duplex receptacle (wiring device) count in a box fill calculation?

Accepted Answer

Two conductors based on the largest AWG in the box

Answer

NEC 314.16(B)(4) states each wiring device (switch or receptacle) counts as two conductors based on the largest AWG conductor present in the box.

Question 3

Per NEC 314.16(B)(5), all equipment grounding conductors (EGCs) inside a box collectively count as how many conductors in box fill?

Accepted Answer

One conductor based on the largest EGC present

Answer

NEC 314.16(B)(5) requires all EGCs together to be counted as a single conductor based on the largest EGC in the box.

Question 4

A 4-inch square metal box 1-1/2 inches deep has a listed volume of 21 cubic inches. Using only 12 AWG conductors (no devices or clamps), how many conductors are permitted?

Accepted Answer

9 conductors

Answer

Each 12 AWG conductor occupies 2.25 cubic inches; 21 ÷ 2.25 = 9.33, which rounds down to 9 conductors maximum.

Question 5

Per NEC 314.16(B)(2), how do all internal cable clamps inside a box count toward box fill?

Accepted Answer

One conductor (all clamps together) based on the largest AWG in the box

Answer

NEC 314.16(B)(2) requires all internal cable clamps as a group to count as a single conductor based on the largest wire size in the box.

Journeyman Electrician’s Exam Practice Test

Journeyman Electrician’s Exam Practice Test

Journeyman Electrician’s Exam Journeyman Electrician's Boxes and Enclosures