0

I've been reading up on NEC 2023 - and possibly misunderstanding, and the 2023 doesn't apply to my area anyway (...yet). My current reading of 210.12 suggests that NO 240v circuits require AFCI: is this correct?

That said, I'm contemplating a few possible electrical designs right now, probably going over the top. If I DO want to implement both AFCI and GFCI protection on a 240V 50A circuit (such as for a range or a clothes dryer), what are my options?

I can't find any combination-function breakers that are 240V, much less high enough current.

I can't find any GFCI outlets for 240V.

Could I get deadfronts for AFCI and another for GFCI prior to the receptacle? If it exists, a deadfront GFCI might be cheaper than the GFCI breaker - and I will need at least GFCI.

Maybe this is a moot point given the code doesn't require this, but I'm trying to learn and want to see what options exist.

(As a side note: my reading of (2023) 210.12.A.4 suggests that a listed AFCI outlet is fine (and protecting downstream outlets?) if the breaker is listed and the run to the outlet is continuous (unspliced) and 50ft or less for 14AWG or 70ft or less for 12AWG, assuming you label the outlet. Not sure where I can get the list of what qualifies for 210.12.A.4.d, though - can somebody correct or clarify? If this is the case, what's the point of the the metal sheathing described in 210.12.A.5?

2 Answers 2

1

As already stated in ThreePhaseEel's answer, AFCI simply doesn't exist, at least not at the mass production level, for circuits larger than 20A. If NEC ever requires it then manufacturers will build it, but until then I would not expect to see AFCI for 240V (any size) or 120V larger than 20A.

When it comes to GFCI, the current general situation is:

  • GFCI/deadfront, GFCI/receptacle, GFCI/switch - only for 120V 15A and 20A.
  • GFCI/breaker - readily available for 120V 15A and 20A (so you get to pick where you want to place the GFCI protection) and mostly for 240V 15A and 20A (which takes care of MWBC and similar situations).
  • GFCI/breaker - gradually becoming more readily available for most panel types for 240V larger than 20A.

The last one is the key. NEC 2020, which has been adopted in many places, requires GFCI for new 240V receptacles, which really means GFCI/breaker because there are no (at least not readily available) 240V GFCI/receptacles. This has become a major concern for EV charging (EVSE is the official term). In fact, this is a big reason, aside from other very practical reasons (and often the installation instructions of the EVSE) to hardwire EVSE rather than installing a receptacle. (My electrician has a real horror story about dealing with that for a customer in a NEC 2020 area who insisted on a receptacle for future EVSE where he had serious problems getting a proper GFCI/breaker.) That can also be a reason to hardwire other equipment, such as cooking equipment.

Clothes dryers are an interesting twist. Do they really need GFCI? Probably not so much due to the nature of the equipment. However, clothes dryers continue, decades after the rules were changed, to have the "3 wire vs. 4 wire" problem. GFCI is actually a solution to that problem, but GFCI requirements for 240V receptacles are definitely the type of thing that only applies when a circuit is added or substantially changed, and actually changing to a 4-wire cord, plug and receptacle can usually be done (unless there is no ground wire and no easy way to add a ground wire) for a lot less than the cost of a GFCI. So the new requirement won't actually help the people who really need it, with one exception: Someone has a new house with a GFCI/breaker protected 4-wire dryer receptacle, gets a used dryer with a 3-wire cord/plug, changes the receptacle (instead of properly changing the cord/plug, which is easier and cheaper!) and finds that it simply won't work because the GFCI won't work with neutral/ground bonded. (Chaos ensues, followed by a hefty electrician's bill to switch back to 4-wire, etc.)

3
  • This is definitely quite expensive, but I have found 50A GFCI for 240V, like the HOM250GFIC ($110 at time of writing, amazon link here but dunno if it'll remain functional for long: amazon.com/HOM250GFIC-Circuit-Breaker-Square-Homeline/dp/…)
    – user112697
    Commented Apr 19, 2023 at 14:16
  • One problem is that the breaker has to match the panel - there are several major types out there (Square D x 2, Eaton x 2, GE, Leviton) and many older types are compatible with (really just name changes and updates) newer types but there are also breakers that will "mostly fit" a different brand but that is against code as "mostly" isn't good enough when it comes to high current 120V connections. Commented Apr 19, 2023 at 14:20
  • 1
    Yeah, I've been digging through what panel I wanted to install and settled on homeline on account of having the most affordable CAFCI breakers, so I guess I'm locked into that ecosystem now.
    – user112697
    Commented Apr 19, 2023 at 14:21
3

AFCI doesn't go above 20A at all

AFCIs are intended to provide "tighter" protection for ordinary branch circuits with their large number of splices and other potential points of failure, so they are only made in 15A and 20A versions to begin with. This isn't an issue, though, since very few >20A branch circuits in North American residential practice have all that much going on -- even when they aren't a dedicated branch circuit, they will only have a small handful of devices and splices on them.

I'd just run a modern armored or metal-clad cable anyway

If you're that paranoid about your circuits, I'd simply grab an appropriate armored or metal-clad cable and run that instead. (Sadly, MCI-A type cables aren't available for circuits upwards of 30A, or else I'd recommend those as they provide a good balance of easy termination, good fault handling, and physical robustness.)

1
  • This is excellent info, thank you! I think I'm going to accept the other answer because it provides more detail about GFCI, too, but I wish I could accept both.
    – user112697
    Commented Apr 19, 2023 at 14:15

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.