Ok, is please bear with a little explanation:

My girlfriend had the master bath in her condo remodeled, and asked her contractor to install a new (GFCI) outlet. He apparently pulled it from the switch for the vanity light fixture. At the same time, he installed a dimmer switch for that same vanity light. The good news is there is no buzzing from the light fixture at all. The bad news is that the new outlet is buzzing and crackling like mad. These people told her there was nothing that could be done, and that it wouldn't hurt anything, it was because the dimmer and the GFCI amounted to two transformers on one circuit. This is a crock, but I wasn't around when the work was done. At this point I am wondering if anything can be done without pulling out the new sheetrock. The GFCI outlet works fine, it tests and resets normally, and you can use it nomally as well. It just sounds like an angry beehive. I was considering a lamp debuzzing coil, but my only experience with one of those, it made as much noise at this outlet is. Any suggestions?

  • This question might be worth a look. – Tester101 Aug 1 '11 at 12:08

I have never encountered the situation of a buzzing GFI before. Sounds a bit fishy to me. The trouble shooting procedure would be to turn off the power to the bathroom, unscrew the GFI from the box, pull it out a bit and remove the "load" side wires which should go to the dimmer and check that "line" screws are tight. Turn the power back on, if the dimmer is on the load side then the light with dimmer should be inoperative. Does the sound go away? If it doesn't and the buzz remains, the GFI is probably defective. Now turn the power back off, put the load wires back on and test again. If the buzz comes back then replace the dimmer or swap it for a regular switch. If neither of these subtitution tests stop the problem, call a different electrician. Trust me, a buzz from a GFI or a dimmer is not a normal situation and could be a potentially dangerous situation. Feel free to ask follow up questions if any of this doesn't make sense to you. Maybe one of my buddies can do an edit to make this a bit easier to follow.

  • It's worth noting: the thing buzzes even when it is tripped with the test button, just keeps on . . . – OtherMatt Jul 31 '11 at 22:03
  • do the lights go out when you trip the GFI? – shirlock homes Jul 31 '11 at 22:34
  • no, they don't change at all. – OtherMatt Jul 31 '11 at 22:45
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    It sounds like either a bad connection (which should be fixed immediately, as it's a fire hazard), or a faulty GFCI (which also should be fixed - faulty is not a good quality in safety devices). – gregmac Aug 1 '11 at 1:37
  • The lights are not on the load side, be aware. Did you do the tests I suggested? Would love to hear some feedback. – shirlock homes Aug 1 '11 at 21:37

I noticed several kitchen outlet GFIs all buzzing slightly yesterday. They buzzed both while ready and while tripped. I didn't check the wiring but they are all about one year old, installed by an electrician. I pulled one out, and it was cool to the touch.

This morning the buzzing had stopped!

I think the incoming line voltage may have varied and the GFIs buzzed when the voltage was a little low.

  • 1
    Why would a Gfci buzz with low voltage? Voltage swings are pretty normal, I've never noticed any Gfci buzz – Steven Dec 25 '12 at 23:07

Checking the wiring is one of the first things to do. If you have the GFCI setup as a 'no equipment load' (the last load on the leg or additional loads are tied to the line side of the GFCI and not the load side) then make sure the load posts are not near any wiring in the box. Also, if you are sharing the load posts for future wiring (either to another GFCI or by chance a future load that is not supposed to be protected (old code)) make sure there is nothing plugged in that could cause feedback.

TL/DR: I had a GFCI that started to quiet buzz several months after installing. It was one of many GFCIs in my bath all independent (load and line wires shared load posts). My load posts were unused, however they were not screwed in and were sticking out. As a result, when the 20amp 12g wire was pushed into the box I believe the ground wire was close to the load post. There was the original sticker on the load posts (hot and neutral) however the sticker came loose from the hot post. I removed the receptacle and screwed the posts in, and reaffixed the sticker to the post, and ensured the ground and other wires were properly pushed into the back of the box. The buzz is no longer present.

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