15 Amp Recepticle on a 20 Amp Circuit

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rwooten

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In a house recently built, the electrician had a 15 Amp rated outlet that on the back reads #14 AWG wire for the push in connection or #14 or #12 AWG wire to be used on screws. He then put this on a 20 Amp circuit. Can a 15 Amp device be put on a 20 Amp Circuit? To me, the overcurrent device should be rated to the weakest link in the circuit, which would be the 15 Amp rated outlet.
 
Re: 15 Amp Recepticle on a 20 Amp Circuit

To me, the overcurrent device should be rated to the weakest link in the circuit, which would be the 15 Amp rated outlet.
Normally that is true.

A few items to think about.

You can not insert a 20 amp plug into a 15 amp receptacle. This alone should keep the load to less than 15 amps for one particular receptacle.


The feed through rating of a 15 amp duplex receptacle is 20 amps.


The NEC gives us direct permission in 210.21(B)(3) to use multiple 15 amp receptacles on 20 amp circuits.
 
Re: 15 Amp Recepticle on a 20 Amp Circuit

Very few if any items in the average home have a 20 amp plug.Now if he puts a 20 amp receptacle on a 15 amp circuit that would be a violation as it indicates 20 amp loads are supported.
 
Re: 15 Amp Recepticle on a 20 Amp Circuit

Now if he puts a 20 amp receptacle on a 15 amp circuit that would be a violation as it indicates 20 amp loads are supported.
I'm going to try and find a thread that I started some time ago where I made this exact statement and many argued against me. Jim, as you have mentioned there are not many 20 amp rated appliances that are used in a residence and Bob (iwire) made note that the feed thru terminals of a 15 amp receptacle are rated at 20 amps. Now, having said that, isn't it logical that if you install a single or duplex 20 amp receptacle shouldn't you have run # 12 wire to it ? After all, you can only install a 15 amp plug in a 15 amp receptacle but you can install either a 20 or a 15 in a 20 amp receptacle. If you install a 20 amp plug into a 20 amp receptacle and ran only #14 wire to it, won't the insulation break down sooner rather than later ???
 
Re: 15 Amp Recepticle on a 20 Amp Circuit

Are you talking about the wire or ocpd? In one local they require all 12 as a min. NO 14. If the receptacle is a single 15 and a 15 amp breaker there is nothing wrong with 12. If you installed a 20 amp breaker and 12 wire, I believe you have to install a 20 amp rated receptacle if it's a single. Check out 210.21(b)(1) Single receptacle on an individual branch circuit.

Hank
 
Re: 15 Amp Recepticle on a 20 Amp Circuit

If you install a 20 amp plug into a 20 amp receptacle and ran only #14 wire to it, won't the insulation break down sooner rather than later ???
Not if the circuit is protected with a 15A OCPD. A 30A receptacle could be installed on a 15A circuit without any danger to the conductors. However it would mislead users to assume there were 30A available.
 
Re: 15 Amp Recepticle on a 20 Amp Circuit

I can see what all you have mentioned to be true, but this is in a garage, that may someday be used as a shop, so therefore if two devices each pulling 9 amps were to be running simultaneously, we would then be using this recepticle above its designed rating. who would be at fault if a fire were to result in this code loophole?
 
Re: 15 Amp Recepticle on a 20 Amp Circuit

Each receptacle on a duplex is UL listed for 15 amps, not the whole duplex but each individual receptacle. And by table 210.21(B)(2) allows each receptacle to be loaded to a maximum of 12 amps which would trip the 20 amp breaker.

As for the 20 amp single receptacle on a 15 amp circuit the only thing I can justifiy this is to allow a 100% load on a 15 amp circuit as a 15 amp receptacle is only allowed to be loaded to 12 amps but 210.23(A)(1) would still only allow a single receptacle circuit to be loaded to 80% so that wouldn't work?
But when I read 210.19(A)(1) It say's:
Branch-circuit conductors shall have an ampacity not less than the maximum load to be served .
Could this be read as saying that since a 20 amp single receptacle can be loaded to 16 amps it would overload this circuit and violate this rule?
I have no idea why the NEC was left open as to this but other than this I can not find anything that say's a 20 amp single receptacle cannot be used on a 15 amp circuit except in 555.19(A)(3) for Marinas, and found in this thread: Marinas
 
Re: 15 Amp Recepticle on a 20 Amp Circuit

At school, we have a series of 30A twist lock recepticles, would it be wrong to use them alone on a 15A circut, with #14 wire, just because the recepticle is rated for 30A? The expected load is only 10A max, even if it exceeded this, and passed 15A, the breaker would trip before any damage was done to the wire? Is this not the same case with using a 20A recepticle on a 15A circut?

[ December 15, 2004, 01:02 AM: Message edited by: bensonelectric ]
 
Re: 15 Amp Recepticle on a 20 Amp Circuit

However it would mislead users to assume there were 30A available.
Electricman2, this is the whole point to the argument. While we electricians may design and install a given circuit and receptacle for a specific purpose, once we walk away from that job we leave behind the potential that John Q. Public will come along and plug in some device with a 20 amp attachment plug (although rare as it may be) and burn up the wire. Of course you could make the argument that the OCPD that YOU installed at the breaker panel is only 15 amps but then my question is "Why?". :roll:
 
Re: 15 Amp Recepticle on a 20 Amp Circuit

Matt, the expectation would be that 30 amperes is available so it is not permitted to use any type of 30 ampere receptacle on a 15 or 20 ampere circuit. Take a look at 210.21(B) and Table 210.21(B)(3). :D
 
Re: 15 Amp Recepticle on a 20 Amp Circuit

Charlie I may install a single 30 amp receptacle on a 15 amp circuit. 210.21(B)(1).

210.21(B)(2), Table 210.21(B)(2) and 210.21(B)(3) only apply to branch circuits supplying two or more receptacles.

Seems strange to me but that is how it reads.

Edit; forgot to post 210.21(B)(3) :eek:

[ December 15, 2004, 06:44 AM: Message edited by: iwire ]
 
Re: 15 Amp Recepticle on a 20 Amp Circuit

Posted by Iwire:


Charlie I may install a single 30 amp receptacle on a 15 amp circuit. 210.21(B)(1).
It does seem to read that way. But you wouldn't be able to plug anything into that receptacle per 210.23(B). :D

If it has a 30A plug, I think we can assume the load would be greater than 16A. Thus, it is prohibited by the last sentance.

Steve
 
Re: 15 Amp Recepticle on a 20 Amp Circuit

Not allowing a 20A receptacle on a 15A circuit makes sense, but the code allows a 50A receptacle on a 40A circuit. Explain that one. :)
 
Re: 15 Amp Recepticle on a 20 Amp Circuit

Because they don't make a 40 amp receptacle and you can't use a 30 amp receptacle for the 40 amp load, so you have to go to the next size up. In a residential application the only time I would use one of these is for an electric oven/cooktop. Most of the time (at the time of rough-in) the builder can't tell me what size the unit is so I end up running 6/3 anyway. That way I'm covered whether it's a 40 or 50 amp circuit. The cost of the wire (up front) is a lot less expensive than if you ran 8/3 and had to rip it out because the homeowners purchased a unit that requires 50 amps.

[ December 15, 2004, 05:34 PM: Message edited by: goldstar ]
 
Re: 15 Amp Recepticle on a 20 Amp Circuit

Originally posted by steve66:
Posted by Iwire:


Charlie I may install a single 30 amp receptacle on a 15 amp circuit. 210.21(B)(1).
It does seem to read that way. But you wouldn't be able to plug anything into that receptacle per 210.23(B). :D

If it has a 30A plug, I think we can assume the load would be greater than 16A. Thus, it is prohibited by the last sentance.

Steve
Steve I stick by my statement, A single receptacle of 30 amp rating may be installed on a 15 amp circuit. :D

A receptacle is not a 'load' it is only a device. :D
 
Re: 15 Amp Recepticle on a 20 Amp Circuit

Steve 210.23(B) only applys to a branch circuit that has a rating of 30 amps. The branch circuit in question is only a 15 amp circuit. Remember the OCPD is what sets the rating of a branch circuit, and if you have a 15 amp breaker then you only have a 15 amp branch circuit so 210.23(B) would not apply.
 
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