?
Wednesday, January 19, 2022
Question:
Good Day and Happy New Year CQD.
The question today seeks to address device fill-in outlet boxes. How nay conductor deductions are required for a larger device such as a receptacle equipped with USB ports? These devices are significantly deeper than standard receptacles. Does the NEC allow for this?
Bill Kohl
A
Answer:
Hi Bill,
Your observations and intuition are correct. The NEC has been revised recently to address devices that are significantly larger than standard devices, such as the ones you mentioned which contain a power supply for the USB ports. GFCI and AFCI devices and some lighting controls could sometimes fall into the category too. Section 314.16(B)(4) indicates that for each yoke or strap containing one or more devices or equipment, a double volume allowance in accordance with Table 314.16(B) shall be made for each yoke or strap based on the largest conductor connected to a device(s) or equipment supported by that yoke or strap. A device or utilization equipment wider than a single 50 mm (2 in.) device box as described in Table 314.16(A) shall have double volume allowances provided for each gang required for mounting. So depending on the width of the device, a double (maximum size conductor in the box) volume allowance could be required.