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A 5-20(20a) receptacle is legal on a 15a circuit?
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Joined: Jul 2004
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G
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Someone pointed out to me that it seems so if it is a single receptacle.
210.21(B)(3) table would seem to say no but 210.21(B)(3) text says that table only applies to circuits with more than one outlet.

Quote
201.21(B)(1) Single Receptacle on an Individual Branch Circuit. A
single receptacle installed on an individual branch circuit shall
have an ampere rating not less than that of the branch circuit.

Quote
210.21(B)(3) Receptacle Ratings. Where connected to a branch circuit
supplying two or more receptacles or outlets, receptacle ratings
shall conform to the values listed in Table 210.21(B)(3), or,
where rated higher than 50 amperes, the receptacle rating shall
not be less than the branch-circuit rating

What are we missing? Can I run a 14a circuit with a single 20 receptacle on it?


Greg Fretwell
2017 / 2014 NEC & Related Books and Study Guides
Joined: Jan 2018
Posts: 26
L
Member
Wording of 210.21(B)(1) does appear to permit the rating of a single receptacle on a dedicated circuit (“individual branch circuit”) to exceed the circuit rating, but there would of course be no point to doing so due to the OCPD. In addition, 210.22 specifies that the load on a dedicated circuit must not exceed the circuit rating.

Note that the commentary on 220.21(B)(1) in the NEC handbook has an example of a 20A circuit and they don’t even consider the possibility of the receptacle rating exceeding the circuit rating. They simply say the receptacle must be rated at 20A in accordance with 220.21(B)(1).

Fortunately, duplex outlets have two receptacles, so they they fall under 210.21(B)(3) where there is no interpretation ambiguity.

Joined: Jan 2018
Posts: 26
L
Member
Whoops - I meant 210.21(B)(1) in that second paragraph (not 220.21).

Joined: Jul 2004
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G
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The problem is they do not preclude a single 20 on a 15a circuit. It seems NFPA does not even acknowledge the NEMA standard so
"load" doesn't enter into it. They do have the unenforceable limits on what a user might plug in but the installer and inspector are long gone by then. I guess they just want to be sure the receptacle won't burn up and leave it at that.
In the 23 code the draft I looked at even removes more language from 210.21. "Not greater than" is gone from the 15a row of the table even for multiple receptacles.
I think some of the changes in the 1st draft might not survive the comments tho.
They changed 210.12 to pretty much say AFCI shall be provided without listing any particular circuits that it applies too.


Greg Fretwell
Joined: Jan 2018
Posts: 26
L
Member
Yeah...that 210.21 wording is an oddity. Did a bit of searching and I see that from time to time others have questioned its intention as well.


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