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15/20amp Recepts

Posted By: aldav53

15/20amp Recepts - 12/21/04 06:09 AM

Old subject probably but can 15 amp recepticles be used on 20 amp circuits like a kitchen circuit.
I believe 20a recepts are usually used in a dedicated circuit, single or duplex.
15 amp GFI's say they can be used with a 20a feed thru circuit.
Posted By: Norstarr

Re: 15/20amp Recepts - 12/21/04 06:30 AM

53, A duplex receptacle rated 15 amps can be used on a 20 amp circuit such as in a laundry room for the appliance circuit. You can not use a single 15 amp receptacle on a 20 amp circuit though. It must be rated 20 amp. All duplex receptacles in a kitchen, including the GFI's can be rated 15 amp. Hope this helps.
Posted By: SolarPowered

Re: 15/20amp Recepts - 12/21/04 07:39 AM

Also, a duplex receptacle counts as two receptacles for the purposes of this discussion, so it is OK to have a single, 15 amp, duplex receptacle on a 20 amp circuit.
Posted By: Ryan_J

Re: 15/20amp Recepts - 12/21/04 02:06 PM

See 210.21 and 210.24
Posted By: DougW

Re: 15/20amp Recepts - 12/21/04 08:27 PM

You can always have a smaller (ampacity) receptacle on a larger(ampacity) circuit, but you can't have a larger (ampacity) receptacle on a smaller(ampacity) circuit.
Posted By: Norstarr

Re: 15/20amp Recepts - 12/21/04 08:40 PM

DougW, Says who? I think you are quite wrong about that. Maybe if you explain in a little bit more detail it will make sense. According to your statement I can put a 20A 230 volt 3 phase TL receptacle on a 30 Amp 230 volt 3 phase circuit. No way. I'm sure you just used the wrong wording.
Posted By: iwire

Re: 15/20amp Recepts - 12/21/04 08:46 PM

Ron actually you can put a single receptacle of higher ampacity then the circuit it is connected to. [Linked Image]
Posted By: George Little

Re: 15/20amp Recepts - 12/21/04 10:15 PM

Mr. IWIRE, I am looking for an example where you'd put a higher rated single receptacle on a lower rated individual branch circuit and I'm not finding any. Except for the exceptions in 210.21(B)(1). And I'm not sure that's even an argument in your favor. Please educate me [Linked Image]
Posted By: iwire

Re: 15/20amp Recepts - 12/21/04 10:47 PM

George that is twice today I have been called Mr.

Please call me Bob [Linked Image]

First I did not say it was a great idea but lets look some of 210.21(B)

210.21(B) Receptacles.
(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.

Notice they did not say the same rating as the branch circuit or the values in Table 210.21(B)(3).


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 larger than 50 amperes, the receptacle rating shall not be less than the branch-circuit rating.

IMO it is clear the requirements for single receptacles have nothing to do with Table 210.21(B)(3).

IMO single receptacles and multiple receptacles rated over 50 amps may be supplied with branch circuits rated lower than the receptacle.

I would have to ask what code section prohibits using a single 30 amp receptacle on a 15 amp circuit.

An engineer once wrote in asking if he could feed a 200 amp pin and sleeve receptacle with a 90 amp branch circuit.

No one could find a code section preventing that.


[This message has been edited by iwire (edited 12-21-2004).]
Posted By: SolarPowered

Re: 15/20amp Recepts - 12/21/04 11:41 PM

That does actually make sense. A 200 amp receptacle protected by 90 amp fusing will be safe. The reverse would not be--a 90 amp receptacle protected by 200 amp fusing is in danger of being overloaded.

I think that the confusion that arises comes from the concept that a 200 amp load is going to be plugged into a 200 amp receptacle. When you're dealing with plugs and receptacles in excess of 20 amps, that doesn't necessarily follow. The cord, plug and receptacle are normally often selected at the time of installation; they need to be sufficient for the load, but there is no danger in having them too big.

The fusing is normally selected specifically for the load, so there's not really an issue with the receptacle and fusing having different values.

At 20 amps and below, the situation tends to be different. Specifically, if a load is supplied with a cord with a 20 amp plug, it almost certainly draws more current than can legally be supplied by a 15 amp circuit. And 15 and 20 amp circuits are pretty much generic--you find an existing receptacle in the wall, and plug into it. So, if one were to put a 20 amp receptacle on a 15 amp circuit, there is more of a danger that someone will plug in a load that needs a 20 amp circuit.

[This message has been edited by SolarPowered (edited 12-21-2004).]
Posted By: sgreany

Re: 15/20amp Recepts - 12/23/04 02:04 AM


I have herd some crazy things on this subject in the past. It is easy to confuse switches with receptacles here. Switches, the rating is for the device, with receptacles its the face configureation as well as the feed through capacity. All 15A. residential receptacles are 20A. feed through. I have checked this.

I beleive there should be a code change that 20A. face configuration receptacles should only be allowed as a single device circuit as anything that could use that config such as a copier, will be running neer 80% the circuit capacity rendering the rest of he circuit useless and causing an overload hazard. Besides, even in spec grade situations the 15A. spec grade receptacles are cheaper.
Posted By: gfretwell

Re: 15/20amp Recepts - 12/23/04 06:24 AM

There is no requirement that total load on a receptacle circuit be less than 80%, only that a single piece of equipment be less than 80%. The assumption is the user will keep plugging things in till the breaker trips and unplug the clock.
That is the purpose of 240.4(D). It builds the safety factor into the sizing of the O/C device. Compare 240.4(D) to 310.16 and you see it.
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