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Code Question of the Day

The Code Question of the Day (CQD) is NECA and ELECTRICAL CONTRACTOR Magazine’s flagship National Electrical Code (NEC®) public forum for the industry. The daily distribution of Q&A generates a lively dialogue and shares relative Code-based practical responses.

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September 18, 2026

Question:

Hello CQD, Is an equipment ground necessary for an AFCI circuit breaker to work properly?

The last electrician installed AFCI circuit breaker on a two wire system in a residential.
Whenever anything is plugged in, it tripped the AFCI breaker.

Thanks - Rick S

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September 17, 2026

Question:

Hi CQD, is there really a temperature adder for conduit exposed to sunlight on a roof? The inspector wants a sunlight correction on EMT that is strapped flat to a roof feeding rooftop units, and I cannot find where the added heat comes from in the tables. Thanks, Hank D.

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Answer:

Hello Hank, your install requires adjustment for ambient temperature correction as stated in 310.15(B)(2).  A temperature adder of 60°F is required to be added to the outdoor ambient temperature for raceways when the distance from the bottom of the raceway is less than 3/4 inch above the roof surface; when exposed to direct sunlight.

After the adder is applied, the temperature correction factors of Table 310.15(B)(1)(1) or (B)(1)(2) are used for the final ampacity.

Alternatively, raising the raceway to 7/8 inch or more (shallow strut) above the rooftop surface would remove the need for this temperature adjustment.