1 of 4 bathroom electrical down. All on same breaker.

Hi y'all.

Long time lurker. First time posting on the electrical forum.

So I've come across a strange one today. I have 3 bathrooms and one half bath all in one 20A circuit. Never had a problem till now. 1977 house. In one bathroom (that was a 2009 addition) all power is now out (bank of 4 led ceiling lights, vent fan and a gfci by the sink) are all without power. No other outlets in this bathroom. The other bathrooms are fine so it's not the 20A breaker. I read the sticky above. No odd gfci's in some other place that could have tripped. The gfci in the dead bathroom will not reset. No power to it. I don't recall if that gfci kills power to the overhead lights and fans or not. (Is that normal or abnormal to do that) I pulled the light and fan switch cover (it's a near new dimmer switch for the light bank, and a separate older switch for the vent fan) and checked for loose wires. All are secure on screws And/or wire nuts.

I have not pulled the GFCI to check it (not really sure what I'd be looking for other than obvious disconnected wires).

Only other bit of info I can think of that may be relevant is we have heard a mouse about the house in this area. Trying to catch it. Perhaps he chewed through some wires? Can a mouse chew through solid copper?

What steps should I follow now to logically troubleshoot this. I do have a multimeter and basic electrician tools.

 

Wow, 3 1/2 bathrooms all on one circuit!

In the bathroom with no power I would remove the cover plate from all the outlets and switches and check the wires to see if any incoming are hot. It may be as simple as a bad outlet or loose connection at the first box in the bathroom.

 

Welcome to the forums.

Pretty inconvenient to have that many rooms on a single GFI receptacle. If there is no power to the GFI it won't reset. Start there by checking for power on the line side of the receptacle.

 

It's also possible the mouse chewed through the insulation on the wires creating a ground fault. The GFCI won't reset if there is a continuous ground fault. As mentioned above, first step is to find out if there is power to the GFCI. If there is, then disconnect the load side of GFCI and try resetting it. If it resets, you have a problem downstream. Maybe the mouse...maybe coincidence.

 

Thank you for the responses so far!

Some further detail.

Every other bathroom on this breaker also has a GFCI by each sink. What I meant previously is there are no tripped gfci's anywhere in the house that I can find. None on this circuit for sure.

So I want to get this GFCI thing straight. It is normal and proper for bathrooms wired up IAW Electric Code to make everything in that room lose power when a GFCI trips (or fails)? If so, I gotta be honest, that just makes no sense to me. Why would you want your overhead lighting to go out in the event of a GFCI tripping at your sink? If this does end up being the culprit, (tomorrow I'm going to see if the input to this GFCI is hot, as suggested) would it indicate it was wired wrong and needs to be rewired?

 

No. NEC as modified by the local AHJ. Normally you have only one GFCI per circuit. What you have is not wrong if it is fed from the line side of another GFCI. I'd verify that. If fed from the load side on some older GFCIs it might cause a problem. Lights should never be on a GFCI except for very rare conditions. In fact they can not by code be on the receptacle circuit if the receptacle circuit feeds more than one bathroom.

You have a mess I'd actually consider straightening out the mess and then see if there was still a problem.

 

So based on what I'm understanding here, unless wired wrong, a failed gfci is not likely to cause the lights and vent fan above it to also go out.

So what is the most likely failure here that could cause all these things (gfci, lights, fan) to go out in this bathroom but nothing else in the other 3 bathrooms on the same circuit?

 

HOLD THE PHONE. I figured it out. Or you guys did rather. Thank you!

I'm embarrassed to say that I didn't throughly check all the gfci's after all.
sure enough my upstairs 1977 bathroom had a towel hanging in such a way that it sort of hid that the button was tripped. Pushed it in and power came back on to the whole newer era downstairs bathroom.

So other than having 3 1/2 bathrooms on one 20A which I admit seems excessive, did the electrician wire this newer bathroom wrong by feeding the overhead lights and fan from this gfci? Is there a relatively easy way to have this fixed (separate lights and fan from gfci) without running a whole new line to the main breaker and/or Busting drywall?

 

Yes, in fact none of the bathrooms by code can have lights and fans on the same breaker as the receptacles. It is also considered good practice not to put lights on a GFCI because it is not normally needed. If a single bathroom everything can be on one breaker but only the receptacles need GFCI protection. As stated it changes with more than one bathroom. Lights are not allowed on the receptacle breaker.It would depend on how it is wired. You need new circuits, depending on accessibility you may be able to run them by fishing. Even if you can't fish you never bust drywall except on a sitcom or a TV DIY show. You cut a neat easily patched hole just large enough to do the work.

 

This here is another issue. If there was a GFCI in this bathroom tripped and when you reset it then the power came back on in the bathroom that there was no power with a GFCI in it that you originally reported then the GFCI in the bathroom where there was no power is not needed and may cause issues in the future.

What I mean is you should not be using a GFCI down line from another one if the previous one is protecting "load" down line. Although there really is not a hazard in doing this it can cause "phantom" tripping where the GFCIs trip one another. If there is a GFCI in bathroom one (first bathroom on the circuit) and the"load" is protecting the other bathrooms then no need for GFCIs in the other bathrooms.

If you know the circuit layout then you can simply take the conductors out of the "load" sides of the GFCIs and place them on the "line" sides. This way only the GFCIs themselves are protected and one GFCI to a previous bathroom will not affect another bathroom down line in the circuit.