1

I added an outlet to a bathroom. When I pulled the outlet, which was a 15A, that I was going to tie into it was wired with a #12. I checked the circuit and it is a 20 AMP circuit. It was part of a bathroom that was part of a GFCI. I thought maybe since the was a ground fault that it was okay to have the 15A outlet on a 20A.

I did a little more looking around comparing the circuit to the outlets. It appears that the 20A circuits are all wired with 15A outlets.

Is this a code violation or safety hazard?

Thanks,

Dave

broncosbuck99
  • 11
  • 1
  • 1
  • 2
  • @statueuphemism that link is about a 15 amp circuit. This is about a 20 A circuit which I take to mean it is on a 20 A breaker. – JimmyJames Oct 21 '16 at 14:30
  • @JimmyJames In Tester101's answer, he shows table 210.21(b)(3), which indicates that a 20 A circuit can have 15 or 20 A receptacles – mmathis Oct 21 '16 at 14:31
  • 2
    @JimmyJames Good catch, I misread, but I know it's been asked before. Correct reference is: http://diy.stackexchange.com/questions/12115/is-using-15-amp-components-on-a-20-amp-breaker-against-code?rq=1 – statueuphemism Oct 21 '16 at 14:37
  • @mmathis OK. Can you clarify what is meant by the comment that follows? "It's also good to remember, that the NEC does not view a duplex receptacle as a single receptacle according to the definition of a receptacle." – JimmyJames Oct 21 '16 at 14:37
  • @JimmyJames It means that the duplex receptacle is treated as two receptacles, as 210.21(b)(3) applies to circuits supplying 2 or more receptacles. Circuits supplying a single receptacle (e.g., water heater, dryer, stove) have different requirements – mmathis Oct 21 '16 at 14:43
  • Example of UL listed equipment with a 15 A plug that can pull more than 15 described in [this article](http://www.ecmag.com/section/systems/misleading-circuit) – JimmyJames Oct 21 '16 at 14:58
  • @JimmyJames [The article you referenced](http://www.ecmag.com/section/systems/misleading-circuit) is talking about drawing more current through a 15A outlet than allowed on a *multi-receptacle 15A circuit*, not more than 15A through a 15A receptacle. From the article "NEC 210.23 says: 'Permissible Loads, (A)(1) Cord-and-plug-Connected Equipment. The rating of any one cord and plug-connected utilization equipment shall not exceed 80 percent of the branch circuit ampere rating.'" – statueuphemism Oct 21 '16 at 15:42
  • 1
    Basically, on 15A circuit with multiple receptacles, the maximum permissible single load = 80% * 15A = 12A. So if you had an appliance that drew 12.1-15A from one of the receptacles on a multi-receptacle 15A circuit, this is the unsafe code violation referred to in the article. However, the maximum permissible single load of a receptacle on multi-receptacle 20A circuit = 80% * 20A = 16A. This means that you can safely operate an appliance which draws 15A through a 15A receptacle on a multi-receptacle 20A circuit. – statueuphemism Oct 21 '16 at 15:42
  • Sorry, I'm not following: "maximum permissible single load of a receptacle on multi-receptacle 20A circuit = 80% * 20A = 16A" Are you saying it's safe to pull 16 A through a 15 A receptacle? – JimmyJames Oct 21 '16 at 15:49
  • I apologize for any lack of clarity. I am not saying it is safe to pull 16A through a 15A receptacle. 16A is the maximum allowed to be pulled through a receptacle on a multi-receptacle 20A circuit--however, the maximum current allowed to be pulled through a single receptacle is still limited to the maximum rating of the receptacle. To safely draw 16A on a multi-receptacle 20A circuit, you would need a 20A receptacle. Otherwise, you can safely draw to 15A through a 15A receptacle on a multi-receptacle 20A circuit. – statueuphemism Oct 21 '16 at 15:56
  • @JimmyJames No. It's never safe to draw more current than the receptacle (or device, or circuit) is rated for. He's saying that code specifies the maximum single load in a receptacle on a 20 A circuit is 16 A. This is higher than the rating of a 15 A receptacle, which means that code allows up to 15 A to be drawn from that receptacle. If it were a 20 A receptacle on the 20 A circuit, it would be a violation of code to draw more than 16 A through that receptacle. – mmathis Oct 21 '16 at 15:58
  • @mmathis Right, so I could misunderstand the article but the way I read it was that the author's point is that this device can pull more than 15A despite the fact that it has a 15A plug. Assuming that's right, if you are on a 15A breaker, it should just trip if that happened. That might be annoying. If you are on a 20A breaker, it could pull more than 15A. Maybe this is all corner-case stuff but in my house, I want the breaker to keep things on the circuit from being overloaded. I don't want to depend on my equipment or the shape of the plugs for that. – JimmyJames Oct 21 '16 at 18:08
  • @JimmyJames If something has a plug that fits into a 15A receptacle and is UL listed, it should not draw more than 15A. All the article is saying that appliances which draw 12-15A should not be plugged into multi-receptacle 15A circuits because of the 12A limit per receptacle. The article is pointing out that this is non-intuitive because the appliance plug fits into a 15A receptacle. – statueuphemism Oct 21 '16 at 19:15
  • @statueuphemism You're right. I should have read it more carefully. – JimmyJames Oct 21 '16 at 20:43

3 Answers3

4

Folks, folks...

15A outlets are totally legal on 20A circuits.

Because the NEC makes an exception specifically for that (National Electrical Code): enter image description here

The exception is by careful plan. It would be stupid for electricians to have to carry two types of receptacles on their truck. So UL (the listing agency) requires all 15A receptacles to have internal circuit paths good for 20A. This allows the same receptacle to be used in both 15A and 20A circuits. It also allows two appliances totaling 20A to be plugged in at once, even though each appliance is less than 15A. The extra copper is trivial, they still manage to sell these things as cheap as 60 cents apiece.

If you want a quality receptacle, buy one. You can buy quality NEMA 5-15 (Mr. Horrified) for $3 and up. You don't need to buy a NEMA 5-20 (Mr. Winky) to get quality, but it assures quality since cheapie 5-20's are not commonly made.

Harper - Reinstate Monica
  • 276,940
  • 24
  • 257
  • 671
  • Could you quote the section of the UL standard section which requires all 15A receptacles to have internal circuit paths good for 20A? I know I've seen scattered postings on the internet that the innards are typically the same, but this is the first I've heard of it actually being a UL requirement. – statueuphemism Oct 21 '16 at 19:27
  • 1
    Those docs are intended for component manufacturers, not field installers, and are priced accordingly. An older pirated one found loose on the Web shows it at UL 498 section 107 in several places, particularly `107.2 Each receptacle provided with means for through-wiring on a branch circuit is also to be subjected to a terminal temperature test at a current of 20 A.` – Harper - Reinstate Monica Oct 21 '16 at 21:04
  • Ah, so you just meant the through-current or "pass through" to the rest of the branch circuit. I thought you were indicating that the entire receptacle (particularly at the cord-connection interface) was identical in terms of its current capacity for 15A and 20A receptacles (and it very may well be). You piqued my interest, so I got access to the 2014 copy of UL 231 (Power Outlets). A cursory look-through didn't turn out anything, but I'll see what I can find related to this when I'm up for some more in-depth reading. – statueuphemism Oct 21 '16 at 21:19
  • @statueuphemism I believe UL231 might be the wrong standard -- UL498 is what you want. – ThreePhaseEel Oct 21 '16 at 22:27
  • @statueuphemism I just showed one highlight; 498 says more. I suspect on duplex outlets they are rated for 20A *on any path 20A could happen* (presuming the 5-15 keying prevented >15A over any particular outlet.) Otherwise a 20A breaker would not protect it. It wouldn't surprise me if some lines of outlets had identical guts in their 15 and 20A offerings; that wouldn't be the cheapies though. – Harper - Reinstate Monica Oct 21 '16 at 23:22
1

Most 15 A receptacles are rated for 20 A pass through. So, if you plug something into it, it has to be less than 15 A, but it can safely be installed on a 20 A circuit.

mmathis
  • 8,754
  • 12
  • 41
  • 60
  • 1
    If you plug something into it that pulls more than 15 amps, the 20A breaker will not flip. – JimmyJames Oct 21 '16 at 14:26
  • 2
    @JimmyJames If something pulls more than 15A, if properly manufactured, it should have a plug with a horizontal plug that fits into 20A outlets, but does not fit into a 15A outlet. – statueuphemism Oct 21 '16 at 14:29
  • @statueuphemism Most outlets have two receptacles. – JimmyJames Oct 21 '16 at 14:31
  • @JimmyJames That is correct: Two receptacles rated at 15A each with a 20A pass-through as per mmathis answer. Tester101's answer from http://diy.stackexchange.com/questions/12115/is-using-15-amp-components-on-a-20-amp-breaker-against-code?rq=1 addresses it more thoroughly with code references. – statueuphemism Oct 21 '16 at 14:36
  • @statueuphemism don't use any extension cords, or power strips etc. See the answer farther down from that link. – JimmyJames Oct 21 '16 at 14:44
  • I'd like to remove my downvote here despite my reservations but the system won't allow it unless you edit your response. – JimmyJames Oct 22 '16 at 00:45
-3

This is code but I would change the outlets. Outlets are cheap and easy to replace. Why chance it?

So you can leave this but don't plug more than 2 or more things into one of the outlets that exceed 15 Amps through extension cords or the like. Technically, doing that isn't code but most people who are not electricians don't realize they have to know about this issue. It's crazy that they make people hard-wire smoke detectors in (because people yank the batteries) but expect these same people to not overload an extension/splitter.

Make sure all the other occupants in the house know not to use these:

enter image description here

Or you could just change out the outlets to 20A rated. Another option is that you could change the breaker to a 15A. That will reduce the overall capacity of the circuit, though.

JimmyJames
  • 1,881
  • 1
  • 13
  • 23
  • -1 It adds up quickly if you're replacing all the outlets in your home and it is unnecessary. – statueuphemism Oct 21 '16 at 14:24
  • @statueuphemism if it's just the one circuit then there should be no more than 8 outlets, if I am not mistaken. – JimmyJames Oct 21 '16 at 14:30
  • -1 While it may be true, it doesn't answer the question – mmathis Oct 21 '16 at 14:37
  • 1
    @JimmyJames Even if you upgrade to a 20A receptacle, you have the same potential problem if someone plugs in a single receptacle to multi-receptacle converter like the plug you show. 2 receptacles @ 15A = 30A which is more than either a 15 or a 20A receptacle is rated. – statueuphemism Oct 21 '16 at 15:50
  • @statueuphemism At which point the 20 A breaker should open the circuit. That doesn't necessarily happen if you pull between 15 and 20 (realizing this is not perfectly precise) through a 15 A receptacle. – JimmyJames Oct 21 '16 at 15:54
  • @JimmyJames Good point. +1 based on the edited answer. – statueuphemism Oct 21 '16 at 16:02
  • Just one more thought to throw in along the same vein of your answer, UL-listed single-receptacle to multi-receptacle converters that plug in to a 15A receptacle are not rated to pull more than 15A themselves and would still pose a potential hazard if more than 15A is drawn through them on a 20A circuit. So, if you go this route of precaution, you should also replace all of your 15A single-receptacle to multi-receptacle converters with 20A single-receptacle to multi-receptacle converters. – statueuphemism Oct 21 '16 at 16:25
  • "Why chance it?" Why chance _what_? 15A outlets on 20A circuits are code approved and quite common, so what chance are you taking? – Johnny Oct 22 '16 at 00:07
  • @Johnny there is a fair bit of discussion here that explains what I see as the risks around this. If you want to provide more information in order to dispute the logic laid out here, feel free to do so but your question has already been answered in this thread. – JimmyJames Oct 22 '16 at 00:42