20 amp receptacles on a 15 amp circuit

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goldstar

goldstar

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Location
New Jersey
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Electrical Contractor
While at one of my supply houses the other day I attempted to purchase 1 SINGLE 15 amp, 120V receptacle. Their response was that they no longer stock 15 amp, 120V single receptacles only 20 amp (because the cost is about the same) and that I could use it on 15 amp circuits. Something told me this was incorrect but I was in a hurry and not prepared to argue. After reading table 210.21(B)(3) I believe I'm correct by stating that they are not. Logic tells me that if I run wiring for a circuit rated at 15 amps and install a 20 amp single receptacle, that tells an unsuspecting individual that they can plug in a device requiring a 20 amp circuit which, in all probability will result in an overload. If anyone believes otherwise would you please respond and give your reasoning why.

Thanks,

Phil
 
Re: 20 amp receptacles on a 15 amp circuit

Phil: I read it the same as you. Does anyone know of a household appliance that requires a 20 amp attachment cord?
 
Re: 20 amp receptacles on a 15 amp circuit

Phil

This is one of the reasons why we should not rely on the supply house for our information. You should quote the section and tell them to stock 15 amp receptacles again. You could tell them as an 'argument' that the manufacturers would stop manufacturering the 15 amp receptacles if that was true.

Pierre
 
Re: 20 amp receptacles on a 15 amp circuit

When I bought my first microwave in the 1980s, I almost bought one that had a 20 amp cord and plug.

[ September 24, 2003, 07:07 PM: Message edited by: racraft ]
 
Re: 20 amp receptacles on a 15 amp circuit

Bennie,

I don't recall seeing a household appliance supplied with a 20 amp cord. However, I have seen sewer ejector pumps in basements requiring a dedicated 20 amp circuit.
 
Re: 20 amp receptacles on a 15 amp circuit

Some "window" A/C units have a 20-amp factory cord.
 
Re: 20 amp receptacles on a 15 amp circuit

Thank you all for your responses. The sad part of this is that I asked several of my colleagues and they all believe you CAN use 20 amp receptacles on a 15 amp circuit.

Time for a refresher course !!!
 
Re: 20 amp receptacles on a 15 amp circuit

Goldstar

I know this sounds corny, but that is why I carry a copy of the NEC with me all the time. It is hard for anybody to argue a lost point if the document is right in front of them.

Pierre
 
Re: 20 amp receptacles on a 15 amp circuit

A 15 ampere receptacle can be installed on 125V 20 ampere multioutlet branch circuit, IE more that one receptacle. If there is only one receptacle than it is a individual branch circuit, and the rating of the circuit determines the rating of the receptacle.
 
Re: 20 amp receptacles on a 15 amp circuit

Maybe someone can help me see what I am missing here. I read the initial post as saying a SINGLE receptacle is to be installed on a 15 amp branch circuit. Will this be the only receptacle on the circuit?

If so, 210.21(B)(3) and by reference Table 210.21(B)(3) applies where "connected to a branch circuit supplying two or more receptacles" and thus would not apply here.

If I understand the situation correctly, 210.21(B)(1) would be the applicable section. That section does not reference Table 210.21(B)(3) but only says the receptacle "shall have a rating not less than that of the branch circuit". The 20 amp receptacle meets that requirement.
 
Re: 20 amp receptacles on a 15 amp circuit

Eprice, I can see what you're saying, and agree with you.

Roger

[ September 26, 2003, 05:24 PM: Message edited by: roger ]
 
Re: 20 amp receptacles on a 15 amp circuit

...BUT...

Using that 20A receptical on a 15A circuit would allow a 20A cord/plug device that was plugged in to violate the 80% load rule.

Everything else aside, the 80% rule is the clincher here. In essence, the receptical you choose has to physically reject devices that can overload the branch.

As a practical matter, this is really pretty slim protection since people octopus plug strips all over the place and find lots of other creative ways to overload things and burn their houses down ;-> How many 20A/30A breakers or 30A fuses has everyone found on #14 wire? I've seen this quite a bit in older places.
 
Re: 20 amp receptacles on a 15 amp circuit

Tony, where have we determined (in this thread) this receptacle load is continuous? A 15 amp circuit can be loaded to 15 amps for 179 minutes with no concern.
If it went above 15 amps to say 16 it would open the OCPD.

Roger
 
Re: 20 amp receptacles on a 15 amp circuit

The thing about general use recepticals is you simply don't know what someone will plug in. If you put a 20A receptical on a 15A branch, murphy's law says the dude will go out and buy some big honking 20A A/C unit or microwave and plug the damn thing in.

Years ago, one my fellow engineers at Rockwell had a massive milling machine in his bedroom and plastic all over the floor to catch the chips and cutting oil drips. Curiously, his wife was OK with all this...if he was home milling, I guess he wasn't out catting around ;->
 
Re: 20 amp receptacles on a 15 amp circuit

Originally posted by tonyi:
one my fellow engineers at Rockwell had a massive milling machine in his bedroom and plastic all over the floor to catch the chips and cutting oil drips. Curiously, his wife was OK with all this...
Click to expand...
Cool :cool: what a great wife!
 
Re: 20 amp receptacles on a 15 amp circuit

What seemed to be chrystal clear before now seems kind of gray.

If I understand the situation correctly, 210.21(B)(1) would be the applicable section. That section does not reference Table 210.21(B)(3) but only says the receptacle "shall have a rating not less than that of the branch circuit". The 20 amp receptacle meets that requirement.
Click to expand...
210.21(B)(1) Single Receptacle on an Individual Branch Circuit.
A single receptacle on an individual brance circuit shall have an ampere rating not less than that of the branch circuit.

Reading this makes it clear that you cannot install a 15 amp SINGLE receptacle on an individual 20 amp branch circuit. However, does it also INFER that you can install a 20 amp single receptacle on a 15 amp circuit ? If so, why not a 30 amp receptacle on a 15 amp circuit ? Doesn't that meet this section of the code also ?

I think we have to apply logic here. If you have a 20 amp cord connected appliance requiring a 20 amp receptacle (already installed), wouldn't you want to believe that the electrician who installed this receptacle ran #12 to it ?
 
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