20 amp breaker feeding 15 amp GFI plus overhead lights....questions

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Active Member
Sep 20, 2016
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While doing some investigative work at my fiancée's house, I noticed this. Here's the scoop:

There is a 20 amp breaker feeding a GFI Outlet with 12 gauge wire running from the breaker box to the GFI. The GFI is a 15 amp outlet. Running from the GFI outlet are two overhead track light fixtures connected to a dimmer switch (that's how the lights/switch are getting their power). Nothing else is on the breaker. There is 14 gauge wire feeding the lights and switch from the GFI.

Rather than having to re-wire everything with 10 or 12 gauge, suppose the GFI Is upgraded to 20 amp (vs 15). If there is too much load on the 14 gauge wire or fixtures/switch, that would trip the GFI correct? Is it ok to leave the 15 amp GFI in place or is it better to have a 20 amp GFI? Either way, won't the GFI trip if the load is too much?

As it stands now, the lights can be on for hours and there are no issues and the switch isn't warm at all, it feels normal. Any advice on how to fix this, or should I leave it as is?




Fixer Upper
Staff member
Feb 5, 2013
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Erie, PA
GFCI DO NOT protect for overload. They protect if something like you shorts to ground. The over current device is the breaker in the panel.

What you can do to make it safe IMO would be to change out the 20a to a 15a in the panel. There is no problemwith the wire being too big going to the GFCI.

I'm not a pro so take my advice for what its worth. The pros should be along soon.


Well-Known Member
Nov 19, 2007
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If this is the final setup, you can leave it alone.
Aside from that the easiest, quickest fix is to replace the 20A breaker with a 15A breaker.


Established Member
Supporting Member
Aug 28, 2016
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As mentioned already GFCIs do not protect from overloads. They protect from ground faults (G.round F.ault C.ircuit I.nterrupter). Here is something you can read to get a better idea of how a GFCI receptacle or breaker works.

You can change out the 20amp breaker for the 15amp breaker. Just be sure it is the proper breaker for the panel.

Note: If you wanted to change the 14 to 12 gauge that would be fine but would require a lot more work than changing the breaker. Just be sure though when working in the breaker panel that even though you may shut off the main breaker the feeder wires coming into the panel will still be live. If you swap out the GFCI be sure the circuit is off.

Also, no need to go as high as 10 gauge. 12 gauge is rated for 20amps. 14 gauge is rated for 15amps.

And, by the way just so you know for the future dimmer switches may feel warm to the touch. This is normal. You can read up on this here. There are many articles about this on the net.

May I ask why you were doing investigative work (electrical). Was there another issue that lead you to this discovery?

Does your fiancée own this home?

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