20A receptacle on 15A circuit - OK?

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  #1  
Old 05-15-02, 09:41 AM
HomeownerJ
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20A receptacle on 15A circuit - OK?

I recently had a room addition put on. I asked the builder for 20A service and he complied with 12 AWG wire and 20A "winking" receptacles. OK so far.

Due to the removal of a wall, we had to relocate the receptacles in our existing dining room. 20A receptacles were used, but they were tied into existing 15A circuits. The wiring is 14 AWG.

Is this OK?

If I plug in a 20A load (which is unlikely in a dining room), the 15A breaker will protect me from overloading the wires, right?

To me, it seems that this is no different than plugging two 10A loads into the same 15A receptacle. I would still be relying on the breaker to protect the wiring.

Any thoughts?
 
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  #2  
Old 05-15-02, 01:08 PM
Wgoodrich
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15 amp rated duplex receptacles are allowed on either 15 or 20 amp rated branch circuit in a dwelling. You have no problem with the breaker protecting the conductor if the breaker is sized equal to the ampacity of the conductor. 14 awg must be protected by a 15 amp breaker and 12 awg must be protected by a breaker rated no more than 20 amp. 15 amp duplex receptacles are allowed on 20 amp circuits with 20 amp breakers.

You have an existing condition that may allow this 15 amp branch circuit serving your dining receptacles, that would be a ruling made by your local AHJ [electrical inspector]. However the NEC has required 20 amp rated branch circuits with 20 amp breakers and 12 awg conductors serving those receptacles installed in dining rooms as well as in kitchens, nooks and pantries also must be with branch circuits rated at 20 amps 12 awg serving receptacels in those roooms.

Hope this helps

Wg
 
  #3  
Old 05-15-02, 01:43 PM
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But you cannot put a 20-amp receptacle on a 15-amp circuit. The NEC does not allow it, even though you make a realistic argument as to why maybe they should. Would you like to know how to submit proposed changes for the 2005 NEC? At any rate, you'll need to change the receptacles in the meantime.
 
  #4  
Old 05-15-02, 03:24 PM
HomeownerJ
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I wasn't trying to make the argument that this should be allowed. Being able to plug in a single device that is guaranteed to trip the breaker does not make sense.

But since I will probably never plug in a 20A device (I don't even own one) I was wondering if this condition is acceptable.

Based upon the answers received, I will replace the receptacles with standard 15A ones, regardless of whether or not the 20A ones present a safety hazard.
 
  #5  
Old 06-12-02, 08:46 AM
Bruce McDaniel
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Hi -

By the same token, is it OK to use 20a rated receptacles on a 30a circuit, assuming that 10 gauge wire is used?

Thanks,
Bruce
 
  #6  
Old 06-12-02, 09:05 AM
Bruce McDaniel
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OK - I think I answered my own question - correct me if I am misunderstanding...

The 15/20a rating of the receptacles refers to the type of plug which they will accept, not the amperage which they can tolerate. The AWG rating of the wire determines the load which can safely be carried.

Am I on target here?

Thanks!
 
  #7  
Old 06-12-02, 03:01 PM
Wgoodrich
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20 amp receptacles have a "T" form on one of the spades of hte receptacle that would invite heavy duty plugs designed not to be able to be plugged into 15 amp receptacles. If you have 15 amp wire on 20 receptacles in a dwelling this would invite confusion as to what can be plugged in. Some would plug in a heavy duty load and trip the breaker without knowing why. That is the only reason that I can think up that would forbid 20 amp receptacles on a 15 amp wire.

When you are dealing with 30 amp or more each amp rating has a different configuration of the plug limiting you from installing a heavy load to a light rated receptacle.

We have had discussions concerning this subject. There are referrences in the hand book commentary of hte NEC speaking of installing a 60 amp rated receptacle on a 50 amp rated circuit being allowed because the rating of the receptacle is heavy enough to carry the rated amps of the branch circuit it serves.

confusing to me. Why do we have a receptacle rated in amps for each branch circuit and voltage rating yet we don't use that specific rated receptacle.

Have no firm answer on this one you can interpret either way.

The only place that I know of in the NEC is stating that a 15 amp receptacles are allowed on either 15 or 20 amp rated branch circuits and in the chart 20 amp rated receptacle as the only one listed on 20 amp rated branch circuits. See the following rule found in the NEC 2002. Be aware also that all the configurations are picture in amps and voltage ratings in the handbook of hte NEC 2002 in the same 406.7 article handbook commentary.

406.7 Noninterchangeability.
Receptacles, cord connectors, and attachment plugs shall be constructed so that receptacle or cord connectors do not accept an attachment plug with a different voltage or current rating from that for which the device is intended. However, a 20-ampere T-slot receptacle or cord connector shall be permitted to accept a 15-ampere attachment plug of the same voltage rating. Non–grounding-type receptacles and connectors shall not accept grounding-type attachment plugs.

Confusing but best I have

Wg
 
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Old 06-12-02, 03:13 PM
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There's a little chart in the code. I can't cite it now because I don't have my NEC with me. But if I remember right, it says that:
  • On a 15-amp circuit, you can put at maximum a 15-amp rated receptacle.
  • On a 20-amp circuit, you may put either a 15-amp or a 20-amp receptacle.
  • On a 30-amp circuit, you may only put a 30-amp receptacle.
  • On a 40-amp circuit, you may put either a 40-amp or a 50-amp receptacle.
There's at least one more entry in this table, but I don't remember it.

So the answer to "is it OK to use 20a rated receptacles on a 30a circuit" is "no".
 
  #9  
Old 06-12-02, 05:19 PM
Bruce McDaniel
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Hmmmm. I just bought a house, and the garage has a 30amp circuit run to it. Right now, there are only lights on this circuit, but I would like to add receptacles. Does this mean that I need to reduce the circuit to 20amps to use normal receptacles? What other options might I have (adding a subpanel and splitting it up perhaps)?

Thanks so much for your help!

Bruce
 
  #10  
Old 06-12-02, 05:33 PM
Bruce McDaniel
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Hmmmm. I just bought a house, and the garage has a 30amp circuit run to it. Right now, there are only lights on this circuit, but I would like to add receptacles. Does this mean that I need to reduce the circuit to 20amps to use normal receptacles? What other options might I have (adding a subpanel and splitting it up perhaps)?

Thanks so much for your help!

Bruce
 
  #11  
Old 06-12-02, 07:55 PM
Wirenut33
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Table 210-21(b)(3) of the NEC..... Receptacle ratings for various size circuits:
15A= not over 15
20A= 15 or 20
 
  #12  
Old 06-13-02, 07:01 AM
Wgoodrich
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The NEC also forbids any circuit serving general use receptacles or general lighting in a dwelling to a maximum size of 20 amps. Installing a 30 amp branch circuit to light fixtures in a house would be a violation of the NEC minimum safety standards.

Wg
 
  #13  
Old 06-13-02, 07:56 AM
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Wg, I agree with you, but would appreciate it if you provide the code reference. Thanks.
 
  #14  
Old 06-13-02, 03:55 PM
Jxofaltrds
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John, 210.23 specifically 210.23(B).

Mike
 
  #15  
Old 06-13-02, 05:57 PM
Wgoodrich
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John in addition to what Jxofaltrds listed for a Code article look at

Article 210.24 Branch circuit Summary that calls for mogal base lampholders on any circuit with an amp rating of 30 amps or more. Residential light fixtures are not with mogal base heavy duty light sockets either. So this 210.24.B rule would support 210.23.B that Jxofaltrds mentioned.

Partial copied section of 2002 NEC;

Article 210.24 Branch Circuit Summary

Overcurrent Protection 15 A 20 A 30 A
Outlet devices:
Lampholders permitted Any type Any type Heavy duty

Wg
 
  #16  
Old 06-13-02, 06:47 PM
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Thanks. I guess it'd be okay to put a 30-amp receptacle on a 30-amp breaker, but then you'd be very hard-pressed to find much with a plug that would plug into that 30-amp receptacle.
 
  #17  
Old 06-13-02, 06:54 PM
Wgoodrich
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As far as I know there is no residential rated lighting or general use equipment that is listed and labeled for use with 30 amp receptacles unless they are appliances or other special use equipment not designed to be connected to multioutlet branch circuits such as dryers, water heaters and the like. None of those are designed to connect to a multioutlet branch circuit.

Also you have the concern for fixture wires limited in size for 15 and 20 amp branch circuits that can overheat if loaded on a 30 amp fuse. Same applies to lamp cords of TVs and table lamps designed as general use and plugged into general use multioutlet branch circuits. Those light duty cords would have a melt down if something when wrong causing a 30 amp breaker to trip. Even the fixture wires in a normal light duty light fixture would have a melt down before a 30 amp breaker would trip.

Just adding some comments

Wg
 
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