I'm installing a few new outlets in my unfinished basement and what I have currently is a 20 amp circuit and I have a 20 amp GFCI outlet hooked on to that. I'm looking to add another standard 15 amp outlet off the 20 amp GFCI.

I know you can do 15 amp outlets on a 20 amp circuit but what I'm wondering is it ok to have a 15 amp outlet along with a 20 amp outlet on the same 20 amp circuit as I would want the 20 amp GFCI outlet to provide protection to the 15 amp outlet.


  • 3
    This answer might be helpful. – Tester101 Nov 10 '15 at 21:37
  • @Tester101 thanks, after reading that and a lot of the answer I'm still confused as It seems most are saying it's ok but some are saying not to do it, so I think I'll just go with a 20 amp outlet. – Greenhoe Nov 10 '15 at 22:31

This is legal and will work fine. But you do need to use #12 wire because the circuit is protected by the 20 amp breaker. (you can add more if needed.) I say this because the GFCI outlet is 1 device and the 15 A outlet is the 2nd. If there were only a single 15 amp outlet, it would not be code. But with 2 or more, it is ok. NEC 210-21.b1

  • what do you mean by "and the 15A outlet is the 2nd if there were only 1, 15 amp outlet it would not be code but with 2 or more it is ok." ? – Kris Nov 10 '15 at 21:54
  • Your text states a gfci 20A outlet used to protect a 15 amp outlet, if it was only 1 15 amp outlet on a 20A circuit this is not legal, but with 2 outlets on the 20 amp circuit 1 can be the GFCI outlet and the second one the 15 amp outlet – Ed Beal Nov 10 '15 at 22:17
  • sorry I'm not the "OP", just trying to understand your answer, which unfortunately, I am still unable to. Perhaps if you cited the code violation that would help. – Kris Nov 10 '15 at 22:28
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    @Kris, The answer here quotes the NEC. If you only have ONE receptacle on a 20A branch, it must be 20A rated. If you have two or more, it can be 15A rated. Note that a single duplex receptacle counts as two, so 15A is OK. – JPhi1618 Nov 10 '15 at 22:52
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    I down voted your answer because overall it was nonsensical to anyone unaware of the code article you where trying to cite. It is also lacking structure and syntax. A good bit of up votes are given just on that alone. Unfortunately, I still think it is needs improvement before I change my vote. – Kris Nov 11 '15 at 2:43

If a GFCI device is rated for 20 Amps, that just means that under normal use, it can take up to a 20 Amp load. The Ground Fault part of the GFCI is to detect and prevent a current (Amps), which is strong enough to severely injure a human, from going to ground. If you put a paperclip in the short prong side of an outlet, the GFCI should protect your life (but don't try it). A GFCI device is supposed to detect and interrupt a current as small as 6 mA. See here for more info about GFCIs.

The normal operating load of a GFCI device is always much, much greater than the fault detection part of the GFCI device. 15 or 20 Amps, makes no difference. Your 20 AMP GFCI will fully protect your 15 Amp outlet.

  • 1
    Edwin, your description and understanding of how a GFI works is wrong. The circuit ampacity and device capacity have NOTHING to do with how a GFI works. GFIs detect a current (amps) imbalance in the normal workings of the circuit.See the link you yourself posted for how GFIs work. – Speedy Petey Nov 11 '15 at 12:33
  • @SpeedyPetey, I think you might be misreading my answer. – Edwin Nov 11 '15 at 15:54
  • OK, how so?.... – Speedy Petey Nov 11 '15 at 16:09
  • @SpeedyPetey Because you seem to think that I said that "circuit ampacity and device capacity" had something to do with how a GFCI device works. I said the opposite: "15 or 20 Amps, makes no difference" – Edwin Nov 11 '15 at 23:36

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