I know that NEMA 14-60 plugs and receptacles exist, but they seem really rare. I've come across a few random online forums where people say that this is because they're not allowed by code, since any load of more than 50 amps must be hardwired in residential settings. Nobody has linked to a source for this claim, though. Is this the case under any version(s) of the NEC that are in use in the United States today? If so, where exactly in it is the prohibition?
asked Jun 21, 2021 at 2:21
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4 Answers
You can have a 14-60R in your house, but it must be on a dedicated branch circuit
There is nothing in the NEC that prohibits you from having a 60A (or larger!) receptacle in your house. (While NEMA-style receptacles and plugs only go up to 60A, it is possible to get higher amp ratings in the form of industrial-style pin-and-sleeve connectors.) However, NEC 210.18 requires that receptacle to be on a dedicated (individual) branch circuit (the exception's only useful in factories, so it's not mentioned here):
210.18 Rating. Branch circuits recognized by this article shall be rated in accordance with the maximum permitted ampere rating or setting of the overcurrent device. The rating for other than individual branch circuits shall be 15, 20, 30, 40, and 50 amperes. Where conductors of higher ampacity are used for any reason, the ampere rating or setting of the specified overcurrent device shall determine the circuit rating.
answered Jun 21, 2021 at 4:10
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Well, yeah, how else would you do it? It's not like 15A where most devices use much less than the maximum rating… if you are paying for 60A of conductor, your device is gonna use it! Commented Sep 17, 2022 at 23:45
On top of the very good answer from @ThreePhaseEel, I'd add:
You should probably reach out ahead of time to your local inspection agency, to see what stipulations they'll put on it. They may look into whether the receptacle's safety approvals are "for domestic use" as opposed to a commercial/industrial category. And they may become very concerned that you might be planning to backfeed a generator via a double-male cord, which a disappointing number of homeowners actually try to do. Even if you can show a legitimate use, they may fret that a future owner (or future you) will try it at a moment of crisis. Basically a very-high-amp plug connection into a home's circuits is a red flag for them.
And of course your insurer will want to know about it before you file a claim. They may have concerns not just about the installation of the circuit but whatever it is you're doing with it. If you're welding or running a kiln, you're generating a lot of heat, you may be doing it as a commercial activity, etc. You want all this documented on your policies ahead of time.
If it's for something like a vehicle charger that you're retrofitting with a plug, the insurers and the inspectors may (should) flag that it's not the manufacturer's configuration, which can break your insurance and your approval on top of your warranty. (And if the charger has backfeed capabilities, then please put the receptacle down and head directly to the transfer switch aisle.)
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2A receptacle is a receptacle is a receptacle from the standpoint of UL and the NEC -- unless you're talking Fed Spec or Hospital Grade, there's really not a distinction made in the standards between a commercial/industrial and a domestic receptacle. Never mind that nothing in the NEC prohibits an industrial-grade receptacle in your house! Commented Jun 22, 2021 at 0:00
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@ThreePhaseEeel. Thanks! I may have been conflating with appliance approvals; that big Hobart floor mixer is approved against non-domestic standards. That would be an insurance and liability problem, not electrical code.– CCTOCommented Jun 22, 2021 at 15:40
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1Basically, the only thing I know of that has fairly strictly separate standards for domestic and commercial equipment is kitchen appliances -- in every other case, there's either only one standard, or commercial gear is just treated as "bigger & better" than its domestic counterpart Commented Jun 22, 2021 at 23:50
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1This is for a vehicle charger, but it's one that comes with a 14-60 plug from the factory (and is UL Listed): wattzilla.com/products/black-mamba.htm Commented Jan 13, 2022 at 16:14
The answer turns out to be a little more subtle, because while NEMA 14-60 exists, you can't use it for an EVSE, which is the common forum discussion, because NEC says you can't:
625.44 Electric Vehicle Supply Equipment Connection. Electric vehicle supply equipment shall be permitted to be cord- and plug-connected to the premises wiring system in accordance with one of the following:
(A) Connections to 125-Volt, Single-Phase, 15- and 20-Ampere Receptacle Outlets. Electric vehicle supply equipment intended for connection to nonlocking, 2-pole, 3-wire grounding-type receptacle outlets rated at 125 V, single phase, 15 and 20 amperes or from a supply of less than 50 volts dc.
(B) Connections to Other Receptacle Outlets. Electric vehicle supply equipment that is rated 250 V maximum and complying with all of the following:
(1) It is intended for connection to nonlocking, 2-pole, 3-wire and 3-pole, 4-wire, grounding-type receptacle outlets rated not more than 50 amperes.
(2) EVSE is fastened in place to facilitate any of the following:
Ready removal for interchange Facilitation of maintenance and repair Repositioning of portable, movable, or EVSE fastened in place (3) Power-supply cord length for electric vehicle supply equipment fastened in place is limited to 1.8 m (6 ft).
(4) Receptacles are located to avoid physical damage to the flexible cord.
All other electric vehicle supply equipment shall be permanently wired and fastened in place to the supporting surface, a wall, a pole, or other structure. The electric vehicle supply equipment shall have no exposed live parts.
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3I'm surprised that the NEC's authority extends beyond the building wiring and lets them dictate what you are and aren't allowed to plug in to receptacles. Especially since there are UL Listed 60A portable EVSE's. Commented Dec 11, 2022 at 20:55
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3yeah, I was surprised to find this out myself, since I have a 14-60 charger myself. I am now looking at having to change it to hard-wired I guess, or swap the receptacle to 14-50 and downrate the charger. neither of those are really things I want to do. I wonder if this is going to change as EVSEs get more and more powerful and there's more and more EVs out there. Commented Dec 12, 2022 at 16:17
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2Isn't that a fairly recent addition to the NEC? If you got your EVSE before your state adopted the update with it, wouldn't you be grandfathered indefinitely? Commented Dec 12, 2022 at 19:13
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1@JosephSible-ReinstateMonica It doesn't. The NEC consists almost entirely of instances of them exceeding their authority. It doesn't really matter. What matters is, first, what will and what won't result in you burning down your house or getting shocked, and second, what will or won't result in your local enforcement agency taking action against you. Whether or not they'd have any right to take such actions against you is a matter for philosophers, but being in the wrong won't usually stop them. Commented Mar 16, 2023 at 15:01
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1@jay613 in my case, the EVSE is an OpenEVSE unit ($600) that has a triple-socket cord (14-30, 14-50 and 14-60 compatible). This is a unit that I can take when I move or even on a trip if necessary but still allows me to do 48A when home. Commented Apr 18, 2023 at 13:59
The NEMA 14-60 does exist and has a documented standard as well as approved use cases, but it does not mean it can be used for all installations. Up until 2023, a plug-in EVSE has been limited to a 50A circuit (meaning 40A useable) in North America. Any installation beyond that would be out of code as far as the NEC (National Electrical Code is maintained by the National Fire Protection Agency). Hardwired EVSE limit for an AC EVSE is 80A, requiring a 100A sub-panel. A 60A circuit running at 48A, or a 40A circuit running at 32A, is much more common. No other product, that I know of, runs at max current for hours on end as a standard use case, making this a unique electrical challenge. Continuous current should always be reduced to 80% of the breaker rating.
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I don't think this is a ChatGPT answer (only based on my personal familiarity with the model's "voice"), so I'm curious what makes other people think it is. (And assuming the account is real and not an impersonation, the author actually appears to work professionally on EVSE gear, so I am now almost certain this is NOT an LLM answer, but a human on.) Commented Apr 13, 2023 at 1:22
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Not a great welcome to the site, if I'm right, for someone whose expertise should be genuinely welcomed. Spencer, I hope you write some more answers -- I think you just had bad luck with how this one was received! Commented Apr 13, 2023 at 1:28
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So now if someone assimilates a bunch of useful data in a way that takes knowledge and effort, and presents it in a friendly and slightly chatty style they'll be accused of being a robot because that's what ChatGPT attempts to do. Welcome to the future where a human needs to sound dumber to pass the Turing test. Sorry Spencer.– jay613Commented Apr 18, 2023 at 14:40
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Wow, I guess this got some negative feedback I can't see... Haha. Thanks for the positive feedback from those who followed up. I work in the industry and answer questions like this all the time. I can assure you it was written by me. Commented Jul 9, 2023 at 17:31