Crackling/sizzling noise

[Bodrey]

Recently, when turning on the bathroom light I've noticed a sizzling/crackling noise coming from the GFCI receptacle above the sink. In addition, the light bulb flickers. I plugged my Klein circuit tester into it and it's telling me that the hot and neutral connections are reversed. However, as you can see from the pic all of the black wires are connected to the brass terminal side of the receptacle, and the white wires (neutrals) are connected to the silver terminal side of the receptacle. It appears to be wired correctly.



Now, as you can see there are three sets of cables connected to the receptacle. Two sets of cables branch off and lead to the bathroom light switch and fan...



Is it possible that the wires going to the light and/or fan switches are connected improperly and that that is where the problem lies? Or, is it possible the GFCI itself has become faulty and is throwing out a false "incorrect wiring" signal? The light and fan switches have always worked properly, and it has only been in the last few weeks that the light has started to flicker and that the GFCI has been making the crackling noise. TIA

[TinyTool]

Hi Bodrey!

From the picture, it looks like the wiring is done correctly with the black wires connected to the brass terminals (for hot) and the white wires connected to the silver terminals (for neutral). However, just looking at it doesn’t always tell the whole story. A loose connection might not be visible but can still cause the crackling sound you’ve been hearing, as well as the light flickering.

One of the next steps would be to make sure all the connections are tightly secured. Sometimes, even if everything is wired correctly, a slightly loose wire can cause electrical arcing, leading to the noises and flickering. If everything seems secure but the problem persists, it’s possible that the GFCI itself could be faulty. Over time, GFCI outlets can degrade, especially in bathrooms where moisture is more common, and that might explain the reversed hot and neutral signal from your tester.

I’d recommend checking all the connections first, and if the issue isn’t resolved, replacing the GFCI might be a good idea. If the problem continues even after replacing the outlet, then it could be something to do with the wiring leading to the switches for the light and fan. If that’s the case, it might be worth checking those connections or bringing in a professional to ensure everything is safe.

[Bodrey]

TT - I re-seated all of the connections on both sides. Some of them had a little bit of copper exposed beyond their respective insulation. So, I trimmed them back as necessary. I know these backstab connectors are not reliable, but I tried pulling on each wire before I loosened the screws and they were all secure. However, I think the backstab connectors on this GFCI provide a more secure connection than those on a regular receptacle (they're held in place by tightening the terminal screws). In any event, after re-testing I got the same result - "hot and neutral reversed".

I also checked the connections on the light and fan switches. Although the wires on each of the switches are connected to the backstab connectors and not the terminals, I don't suspect that either of these switches is the problem. The neutrals are firmly secured using wire nuts and electrical tape. The only thing I noticed that was somewhat unorthodox was that there were two pairs of ground wires (tightly bound but not secured with wire nuts) but the two pairs were not bound together. Again, I don't think this is the cause of the fault, but I can take a pic of the light/fan wiring and post it if you'd like to see it.

Moisture could certainly be a factor, and in addition as you stated the GFCI itself could be faulty. I'm leaning towards that as being the problem. Easy enough to swap out to confirm. The one installed is also not of "Weather Resistant" (WR) grade. So, over time moisture may have degraded the connections.

[TinyTool]

Since you’ve taken care of the wiring and you’re still getting that “hot and neutral reversed” error, it’s looking more likely that the GFCI itself could be the culprit. You’re right to lean toward that conclusion, especially since the GFCI isn’t weather-resistant (WR) and has been exposed to moisture over time. Swapping out the GFCI for a new, WR-rated one is a good next step. If it turns out that the GFCI was the problem, replacing it should fix everything. And if not, at least you’ve ruled out that possibility and can focus on other parts of the circuit with more confidence..

Regarding the unorthodox ground wire situation you mentioned, while it's good that the pairs are tightly bound, it might be worth connecting them together properly with a wire nut to ensure there's a solid ground connection across the circuit. It’s a small step, but making sure everything is as standard as possible helps rule out potential issues..

Replacing the GFCI with a WR-rated model seems like your best bet at this point. I’d be interested to hear if that solves the issue, and if not, we can continue troubleshooting from there. Good luck, and feel free to share any more details or pictures if needed!

[Bodrey]

Update:

I bought a new WR-rated GFCI and wired it in exactly the same manner as the old one and I'm still getting the same result with my circuit tester - hot and neutral reversed. Under the pretense that it is in fact wired correctly, I decided to reverse the wires on the light switch (since I observed the sizzling sound coming from the GFCI when the light was on in addition to it flickering). After reversing the light switch wires, I placed my voltage tester near the light switch and the tone was now coming from the bottom terminal, the same as the fan switch. So, then I suspected that the light switch wires had been reversed. However (and again), when I plugged my circuit tester into the GFCI I got the same result. I'm not aware if the orientation of wires on light switches matters, but in this case it didn't make a difference; the light comes on regardless.

The only other thing that I can surmise (and I suspect) is that one of the other two pairs of wires going to the GFCI should be on the Line side, and the pair connected to it now should actually be on the Load side. What say you? Otherwise, I don't know what else I can do to try and rectify the problem. When I put the voltage tester near the brass terminals on the GFCI I got a tone from both the top and bottom.

[machinist]

Hello guys!

Bodrey, firstly, it's crucial to confirm that the wiring is correctly configured between the Line and Load sides of the GFCI. The Line side should receive the incoming power from your electrical panel. This side typically connects to the hot (black) and neutral (white) wires coming from the power source. On the other hand, the Load side of the GFCI should be connected to the wires leading to the light and fan, which are protected by the GFCI. These should also be hot and neutral wires but are meant to provide power to the downstream devices. Since you’ve already tried replacing the GFCI and confirmed the connections at the light and fan switches, the issue likely resides with the configuration of the wires at the GFCI. To address this, turn off the power at the breaker and use a voltage tester to carefully identify which wires are hot and which are neutral. Once identified, make sure that the hot wire (black) is connected to the brass terminals on the GFCI and the neutral wire (white) is connected to the silver terminals. If you have any wires currently connected to the Load side that should be on the Line side, or vice versa, this could be causing the reversed error.

After ensuring the wiring is correct, turn the power back on and test the GFCI with your circuit tester. The new GFCI should correctly identify the wiring if everything is configured properly. If the issue persists despite these checks, it could indicate a more complex problem within the circuit, such as miswiring elsewhere or a deeper electrical fault. At this point, it would be wise to consult with a licensed electrician to ensure the wiring is properly set up and that there are no underlying issues with the circuit.

[TinyTool]

Good to see you back Bodrey. I agree with machinist and I think the next logical conclusion should be to check the GFCI wiring. If the problem persists, it’s possible the issue is upstream in the circuit, like at the breaker or another outlet that shares the same line. Loose or miswired connections anywhere in the circuit can affect the GFCI downstream, so it might be helpful to inspect other outlets or connections that could be part of the same circuit. Another thing to check is the breaker panel itself. Sometimes a loose neutral or ground wire in the panel can cause issues like this. If you're comfortable, carefully inspect the panel to ensure all connections are tight, particularly for the neutral and ground wires.

You should also consider whether the circuit might be part of a multi-wire branch (where two circuits share a neutral wire). If there’s a problem with the shared neutral, it could create the “hot and neutral reversed” error. This might be something an electrician could check for you. Lastly, even though the light and fan switches seem fine, if they’re using backstab connections, those can sometimes be problematic over time. Switching them to screw terminals could provide a more secure connection. It’s also worth ruling out any neutral-to-ground faults in the circuit, as those can also cause GFCI issues.

If none of these steps help, it might be time to call in a professional electrician to take a closer look and ensure everything is wired correctly. Hopefully, these suggestions help narrow down the problem. Let me know how it goes, and feel free to reach out if you need more advice!

Thank you,
TT.

[Bodrey]

Machinist - I do suspect that one of the pairs of wires connected to the Load side should actually be on the Line side, and the pair currently connected to the Line side should be on the Load side. This is the next step I plan to take to try and rectify the problem.

The GFCI has its own breaker at the panel. I don't think there are other outlets as part of the circuit other than the light and fan. Does the orientation of the wires on the switches matter? Earlier today, I decided to swap the wires on the light, and when I did that I got a tone from my voltage tester on the bottom terminal (after swapping). I get the same tone from the same terminal on the fan switch. So, I thought maybe this was the cause of the "reverse" fault, but it didn't make a difference - the issue remained at the GFCI.

[machinist]

Since the GFCI has its own breaker and no other outlets are part of the circuit (other than the light and fan), it simplifies things a bit. As for the orientation of the wires on the switches, generally speaking, the orientation of the hot and neutral wires shouldn't cause the GFCI to show a "reverse" fault—unless there's an underlying wiring issue. Light switches, especially single-pole ones, usually don’t have a neutral connection at the switch itself. They just break the hot connection (or in some cases, the load), so swapping the wires at the switch typically wouldn’t cause this specific issue unless there’s a larger problem in the circuit.

The fact that you got a tone from your voltage tester on the bottom terminal after swapping wires on the light switch is interesting, but since it didn’t resolve the issue, it sounds like the problem may be more with the GFCI wiring than with the switches. It could still be worth ensuring the neutrals in the junction boxes for the light and fan are securely connected with the wire nuts.

If swapping the Line and Load on the GFCI doesn’t fix it, I’d recommend checking for loose connections or grounding issues at the breaker panel. There could be a grounding or neutral issue that’s causing misreadings at the GFCI.

Let me know how it goes, and I hope you get this all sorted out soon!

[Bodrey]

I tried swapping the different pairs of wires on the GFCI today, but it didn't make any difference. Looking at the fan/light box today something strange occurred to me... there are FOUR sets of wires, but only THREE sets of wires in the GFCI. Am I missing something here? Something that also seems strange to me is that the neutral wires are grouped in pairs, just like the ground wires. If all of these cables are part of the same circuit, shouldn't ALL of the neutral wires be bundled together? I've included a screenshot of the box and as you can see there is no pigtail going between the pairs of neutral wires - the pairs are wired in such a fashion to suggest that they're part of two separate circuits which I do not believe to be the case.

The light and fan switches have always worked as they're supposed to, independent of each other. Despite this, I'm beginning to suspect something is very wrong with the way the fan/light switches are wired.

[machinist]

Yes, it sounds like something is off with the wiring. I’d recommend double-checking for another junction box or possibly a hidden outlet on the same circuit that might explain the missing wires. If all the wiring is part of the same circuit, the neutral wires (white ones) should typically be bundled together. The fact that they’re paired without a pigtail suggests the wiring might not be set up correctly and could be acting like two separate circuits. Since the light and fan switches work fine on their own, it’s possible the wiring was done in a way that kept the neutral wires separate, which might explain the GFCI issue. It would be a good idea to trace each wire to see where it’s going and confirm everything is part of the same circuit. If you’re still unsure after that, calling an electrician might help avoid any safety issues.