Observed a 240v receptacle (ev charger) wired with 8awg AL, supplied by a 50 amp gfci breaker.
Generally speaking, the ocpd should be 30 amps for the 8awg AL conductors. Are there any exclusions/exceptions beyond my general knowledge that would make a 50 amp ocpd appropriate for a 240v receptacle?
The length from ocpd to receptacle could be as short as 10 feet, but of course I wouldn’t know for a fact since it is behind drywall.
Thanks!
#8 Al has an ampacity of 35 amps at 60° C or 40 amps at 75° C. The receptacle would need 75° C terminals to utilize the 75° ampacity of the #8 conductors. Either way the 50 amp OCPD is too large.
Thank you, Robert!
I know there are different temperature ratings for conductors, receptacle terminals, etc. that allow different ocpd ratings, however, most of those are still out of my comprehension & memory.
Are there 2 conductors under one lug, asking about the top screw, bottom breaker.
#8 AL seems small and seems strange that it does not seem to match the size of the black. I have not seen a cable that small with AL conductors.
Looks like a GFCI circuit breaker and the integral white wire is coming out of the breaker below the black conductor.
I might agree. I didn’t see the test button.
Yeah, that was 6awg copper used for the neutral on the gfci breaker. Maybe they used some surplus when they trimmed the cable at the top 60 amp breaker.
This home also had a couple 14awg conductors to 20 amp ocpds in the sub. I figured the bozo finished out with what he had on the truck but just wanted to check the 240v receptacle since I knew there were some ampacity differences that I am not totally familiar with.
Thanks to the both of you! Y’all are always a wealth of knowledge & accuracy!
I know that it can be very confusing as there are several variables that can affect the ampacity of the branch circuit. You have the conductor ampacity itself based on the material and size, the terminal temperature limit at each end, and the wiring method (SE cable, NM cable, MC cable, etc.).
