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I've read in various places that 15A receptacles are safe on 20A circuits because the "yoke" (the part that connects the two receptacles to the line) is actually rated for 20 amps.

However, I can't find any documentation for this being true. The Leviton model available at Home Depot only shows 15A on it's spec sheet.

Does anyone have links to any hard evidence of 15A duplex outlets being rated for 20A passthrough? Maybe I'm just not looking in the right places.

References:

Why is it safe to use 15 A receptacles on a 20 A circuit?

https://www.leviton.com/en/products/BR15-W

EDIT: More references

Is using 15 amp components on a 20 amp breaker against code?

https://diy.stackexchange.com/a/114946/172216

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  • @keshlam I think OP is asking if there is any official docs that state this. Quite a few questions/answers say this, but there does not seem to be any that point to something official. We all know that if enough people say something, does not make it true, or else snopes would not be needed. Even if a pigtail was used, there still is the fact of a 15 amp receptacle on 20 amp circuit.
    – crip659
    Aug 19, 2023 at 16:10
  • @crip659: Granted. Though in theory a 15A outlet means nothing drawing more than 15A should be able to plug in at that point, and 15A plugs are already accepted by. 20A outlets... But it would be better to keep this clear and use 20A outlets throughout, so folks are aware they can't count on the breaker blowing at 15.
    – keshlam
    Aug 19, 2023 at 16:16
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    pass-through violates code anyway. It's pigtails all the way down. - That's kinda backwards; a 20amp plug cannot go into a not 20a outlet. You can overload your 15a device on a 20a circuit to your heart's content, because there's a safety factor in there of almost twice, even on 14 gauge wire. What you can't do is plug a 20a grinder into a 15a outlet... because you physically can't.
    – Mazura
    Aug 19, 2023 at 22:16
  • @Mazura — can you expand on ‘pass-through violates code’? Maybe over in chat? Aug 20, 2023 at 13:37
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    @Shane: the "yoke" is the metal (or plastic) part that mechanically supports the 2 receptacles, and is not connected to the circuit conductors except the equipment ground if present, and does not have any current rating.
    – kreemoweet
    Aug 20, 2023 at 14:37

1 Answer 1

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UL effectively requires them to be rated for such

The answer you are after isn't in the manufacturer spec sheets because it'd be redundant there, due to UL test requirements in UL 498. Specifically, either:

  1. 113.2 and 113.4 require a 15A duplex with feed-through capability to have no greater than 30°C of rise at 20A of current when feeding through one set of terminals and out the other, or
  2. you have a 15A duplex that's based on a 20A design, (the common case), and thus is covered by the 20A version's temperature testing (this is effectively an exception to 113.4 in UL 498).
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  • Are there any exceptions to this rule that might come up in old work? It looks like my house has had some major rewiring done at least once before I moved in, and I replaced most of the outlets by now. If I find another 15 amp outlet on a 20 amp circuit breaker then can I assume that the outlet is safe at 20 amps because it is of the NEMA 1-15 type? None of the outlets I've found are so old as to not be polarized, and if I did they'd be replaced based on that alone. I guess one way to phrase the question is this, how far back in time does this rule go?
    – MacGuffin
    Aug 20, 2023 at 19:46
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    @MacGuffin -- I'd assume this rule holds for any outlet of reasonably modern make, but I'd have to look into the history of UL 498 to be sure (which'd take some digging) Aug 20, 2023 at 21:13

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