50A receptacle on 40A circuit okay?

Discussion in 'Electrical Forum discussion & Blog' started by Taylor, Sep 28, 2010.

  1. Taylor

    Taylor New Member

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    Ok to put 50A receptacle on a 40A circuit, #8 wire? My understanding is that NEC allows derating of 50A range on the belief that normally one will not have all rings and ovens going at once. And #6 wire is a PITA hooking up to a receptacle in a junction box.....
  2. Cookie

    Cookie .

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    The Amps that the fixture will draw are found on the rating plate on the fixture. Use the corresponding outlet wire and breaker required for the fixture.
  3. Ian Gills

    Ian Gills Senior Robin Hood Guy

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    I've never seen a 40 amp range receptacle. But like Cookie says, what is critical is what the load requires.

    Nearly all residential ranges require only a 40 amp circuit.

    40 and 50 amp breaker/circuit are basically interchangable. You can use either for a 50 amp receptacle.
  4. Cookie

    Cookie .

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    Range plugs have a specific configuration based on their amps.
  5. Scuba_Dave

    Scuba_Dave Extreme DIY Homeowner

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    My stove...if everything were on...could pull 58a
    Based on the nameplate rating
  6. Taylor

    Taylor New Member

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    Location:
    Northern Joisey
    Thanks all. Rex Cauldwell's Wiring for Pros says that NEC allows derating a 50A range to 40A on the basis that homeowners will never have everything on on the range. So you would run #8 wire from a 40A circuit to a 50A receptacle and plug in a 50A range.

    Cauldwell disagrees with NEC on this, but having tried to wire up a receptacle on #6 wire in a junction box, I can understand why this might be useful.

    In my case, I am looking at a 40A dual fuel range. I was interested in up-sizing for future needs, until I tried it. Just wanted to make sure I did not have to replace the receptacle.
  7. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

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    Any household cooking appliance rated 12kW or less can be used on a 40A circuit.
    Also, to answer the original question, yes, a 50A receptacle can be used on a 40A circuit wires with #8. 40A receptacles do not exist.
  8. hj

    hj Moderator & Master Plumber Staff Member

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    THe amp rating of the receptacle is immaterial. The circuit breaker size is determined by the wire, and as long as those two are proper, you can put any recepacle you want on the end of it. IF you overload the circuit, it will trip the circuit breaker, and that is its function.
  9. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

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    This is not really true. There are strict paramaters as to what receptacles can be used on certain circuits.
    See NEC 210.21(B)(1), 210.21(B)(3) and T210.24
  10. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    While it may not happen too often, but imagine that big party when you've really got all the burners on, and the breaker trips when you don't realize it...could make for a nasty end result. While maybe you can, doesn't always mean you should.
  11. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

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    I've wired a lot of ranges on 40A circuits and I have NEVER heard of this happening. Have you?
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    No, I've not seen it happen. But, his dataplate indicates 58A at full draw. It is unlikely that all burners would be on high, but possible. That's a bit over what a 40A circuit should safely support. Most of my personal experience is with gas stoves...some of the newer ones have more burners, and higher wattage than a typical generic stove.
  13. hj

    hj Moderator & Master Plumber Staff Member

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    quote; That's a bit over what a 40A circuit should safely support.

    Actually ANYTHING over 40 A, is more than the circuit can safely support, which is WHY the circuit breaker should be sized for the wire, NOT the anticipated load.

    That paragraph says that the receptacle cannot be rated LESS than the circuit breaker's capacity, and here is a quote from another area

    A 30A receptacle may be placed on a 25A individual branch circuit. As could a 50A receptacle.

    Which restates what I said previously.
    Last edited: Sep 30, 2010
  14. Ian Gills

    Ian Gills Senior Robin Hood Guy

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    You did not say that. You said you could put any receptacle you want on a circuit as long as the breaker and the wire are sized correctly.

    You could not put a single 15 amp receptacle on a 20 amp circuit, for example. At least I wouldn't.

    Common sense.
    Last edited: Oct 1, 2010
  15. hj

    hj Moderator & Master Plumber Staff Member

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    My mistake. My implication was that he could put HIS oversized receptacle on the end of it, since that was his question.
  16. jimbo

    jimbo Plumber

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    Just remember.....anything you say after hj has the last word, starts a new thread completely!
  17. SteveW

    SteveW DIY Senior Member

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    I realize this is quite correct as far as the NEC, but the logic of it escapes me.

    I don't see how a 15-amp receptacle on a 20-amp circuit is a safety hazard. What am I missing?
  18. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Most receptacles can pass through more current than they can source at an individual outlet and Ian is wrong...you can use 15A devices on a 20A circuit. Although, if you have some one thing that can monopolize the circuit's max current, it's sort of nice to size the outlet for that user.
  19. Artie

    Artie New Member

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    Location:
    Jacksonville, Fl
    For what its worth, twice a year, (Thanksgiving and Christmas), pretty much every burner on the cooktop, and both ovens of the double oven, are going full speed. ;)
  20. jimbo

    jimbo Plumber

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    IN THEORY....a 15 amp equipment could have an internal fault, and since the breaker wouldn't pop until 20, damage or overheating could occur since internally, the equipment is designed to be protected by 15 amps max. This is a stretch of an argument, and the NEC apparently feels comfortable enough to allow it. I do understand that the Canadian Electrical code does NOT allow it.
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