15A outlets on 20A circuits and tandems

[John Coloccia]

1) electric heaters cause fires because they get tipped over, are stuck near drapes/bedding, or are used on wholly inadequate extension cord.

2) The insurance company will say that the house was wired exactly to the NEC. This is how practically every modern home in the USA is wired. Go into your basement and look at all the 20amp breakers. Now look around at how many outlets you have with a horizontal spade plug available.

3) As far as I know, most 15A and 20A outlets are identical, and come off the same line. The only difference is the faceplate, and the only reason the difference exists is to keep someone from plugging a 20A piece of equipment into a 15A circuit. This is required by code and therefore manufacturers happily make different face plates.

And there is no way you're going to melt any metal anywhere unless you're talking about a fuse, and that's REALLY thin metal. Generally, thinner metal heats up and sets the stuff around it on fire, notably plastic insulation and wood.

Finally, as far as I know, UL requires a 15A receptacle to be designed to live on a 20A circuit.

[Bruce Wrenn]

Examine every cord set you have in your house / shop and how many have a 20 amp, 110 plug? None, notta, zero. That is one reason for the 15 amp recpts on a 20 amp circuit. If you put in 20 amp recpts., what would you plug into them? Devices rated for 15 amps or less. Rememeber the Delta contractor's saw that was rated at 1.5 HP on 120, and 2.0 HP on 240. Many said there was some special windings to make it more powerful on 220, but it had to do with getting it rated to have a 120, 15 amp plug. Also, 15 amp rectps can be had for $0.49, while 20 amp recpts cost around six bucks each. That equates to a bunch of money in just one house. Multiply that times the homes in one subdivision.

[Kendall Landry]

Where I live, the breaker can't be rated highter than the wire or the receptical.
Your friend is correct.

[Rollie Meyers]

A 15A single receptacle may not have overcurrent protection in excess of it's rating put 2 or more on a 20A circuit and your OK, BTW a 15 or 20A receptacle guts are the same only the face changes to make them 15 or 20A and 125 or a 250 volt rating, same w/ the cap, if you look closely the only change is the configuration of it, the brass on the blades is the same, this statement is made only for 15 & 20A straight blade devices, nor is it a suggestion to "repurpose" anything because that's what is on hand or whats on sale.

[Rick Christopherson]

Where I live, the breaker can't be rated highter than the wire or the receptical.
Your friend is correct.

Do NOT cite a local code if you have not bothered to take the time to even look up the code for your own locality. All too often, people cite something as being a local code, which was based on a verbal discussion with an electrician or inspector that was taken out of context, but is not actually written code. If it is not written, then it is not code.

Unlike you, I did bother to take the time to look up your local code, and your reference does not exist. Your community has provisions to automatically adopt all new versions of the NEC on April 1 of the year for which it is released. Your local code does list exceptions to the NEC, but 15 amp outlets is not one of them. I scanned through your entire local code.

excerpts from baton rouge electrical code:
Amendment 1: Sec. 210-52-A. Branch circuits for general use shall have not more than eight (8) outlets or fixtures or a combination of both.

Amendment 2: Sec. 210-52-B. Small appliance branch circuits serving the kitchen area shall have not more than four (4) outlets. (No lights).

If you look at a 15 amp and a 20 amp receptacle you will see thinner materials on the 15 amp that if under load could get hot and melt due to the thinner material rated at 15 amps but drawing close to 20 amps before tripping.

No, you will not find thinner conductors on 15 amp receptacles. You are comparing a low-grade 15 amp receptacle to a premium-grade 20 amp receptacle, and confusing the difference between grades as being ampacity differences.

All UL listed receptacles, and they must be UL listed to be used, are capable of sustaining 20 amps. Moreover, the cross sectional area of the metal components on a receptacle is far greater than the cross sectional area of #12 wire. The outlet is not the weak link in the ampacity limitations of a circuit. Actually, the weakest link in a circuit is the compression fitting of the receptacle to the appliance plug.

[Kendall Landry]

Your right Rick, I didn't lookup that particular code. Do you have it? The information came from an Inspecter. A very nice older gentlemen who is a woodworker like his father was. We talked for some 20 minutes.
Its been about a year now. I think he was speaking in generalities and not quoting from his NEC book. He knew it was a workshop so thats probably where the "Make sure you put 20amp receptacles on those 20amp breakers sonny." came from. I don't fault him at all!

Either way, your attempt to gut me like a fish and throw me on the bank was not called for.

[Bill Brady]

You need to pay a little more to get a good quality receptacle. It desn't have to be a specification grade receptacle but you can't pay 59 cents and expect to get a quality product. The receptacle is not rated 15A because of the circuit it is the maximum individual load you can plug into it.

[Tom Godley]

Just because the faceplate of a duplex outlet will not allow anything larger than a 15-amp plug to be inserted does not equate that it is not rated to be wired into a 20 amp circuit protected by a 20 amp breaker. The internals are rated for 20 amp. I have never encountered a 20 amp 110 plug on anything I have ever owned -- I guess some larger window AC units have them ?? Without this ability we would be popping breakers in kitchens all the time.

Fires can be caused by many factors --- using cheap outlets that allow for back wiring where the wire is held with only friction and then looping the circuit through the outlet is a prime cause.

I always pigtail the receptacle -- I especially like the pigtails with the built in wire-nut for outlet installation.