Branch Circuits & WiringQuestion 182 of 521
Using the same 21.0 in³ box with no other fill allowances, what is the maximum number of 12 AWG conductors permitted?
a.10
b.9
c.8
d.7
Explanation
Each 12 AWG conductor requires 2.25 in³ per Table 314.16(B). 21.0 ÷ 2.25 = 9.33, rounded down to 9 conductors. 10 would exceed the volume, and 8 or 7 undercounts.
Law Reference: 2023 NEC §314.16(B)Practice all 521 questions free — no signup required.
Related questions on this topic
- Couplings and connectors used with electrical metallic tubing (EMT) in a wet location must be what?
- An outlet box used as the sole support for a ceiling-suspended (paddle) fan must be what?
- A 4" x 1-1/2" square box has a volume of 21.0 in³. With no clamps, devices, or other allowances, what is the maximum number of 14 AWG conductors permitted in the box?
- Per Table 314.16(B), what is the free-space volume allowance required for a single 12 AWG conductor?
- In a box-fill calculation, a single device (a receptacle or switch mounted on a yoke or strap) counts as how many conductor volume allowances?
- A box contains three internal cable clamps. In the box-fill calculation, how many volume allowances do the clamps require in total?
Last reviewed: · editorial process
PrepPass Editorial Team · Verified against California CSLB C-10 Electrical Trade Examination · How we review