Branch Circuits & WiringQuestion 185 of 521
A box contains three internal cable clamps. In the box-fill calculation, how many volume allowances do the clamps require in total?
a.1 (a single allowance)
b.3 (one per clamp)
c.0 (clamps are exempt)
d.6 (two per clamp)
Explanation
Per 314.16(B)(2), where one or more internal clamps are present, a single volume allowance is required based on the largest conductor in the box — not one per clamp. So three clamps still count as only one allowance.
Law Reference: 2023 NEC §314.16(B)(2)Practice all 521 questions free — no signup required.
Related questions on this topic
- Using the same 21.0 in³ box with no other fill allowances, what is the maximum number of 12 AWG conductors permitted?
- 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 has four 12 AWG equipment grounding conductors entering it. How are they counted in the box-fill calculation?
- A box contains five 12 AWG current-carrying conductors, one 12 AWG equipment grounding conductor, one internal cable clamp, and one switch on a yoke (all conductors 12 AWG). What total box volume is required?
- A single unbroken conductor passes straight through a box without being spliced or terminated. For box fill, it is counted as how many conductors?
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