# Can you tell how this bathroom light switch should be wired based on these photographs?

• posted on May 27, 2008, 6:22 am
Can you tell how this bathroom light-switch circuit is wired based on these 15 highly annotated photos? http://www.flickr.com/photos/27029976@N02/sets/72157605274838278/show /
The wierd thing is that the CGFI circuits (apparently downstream of the light switch) stopped working altogether. There is no current in the GCFI boxes and in adjacent outlets.
Another wierd thing is the voltage CHANGES when the adjacent bathroom light switch is turned on or off (but it does not change if I remove the bulbs from the adjacent light switch).
Can you help me figure out the proper way a light switch should be wired to this box?
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<%-name%>
• posted on May 27, 2008, 6:25 am
On Mon, 26 May 2008 23:22:46 -0700, Donna wrote:

This question is a followup to a previous question on the same topic. All the circuit breakers operate something (although some have tons of circuits on them and others have almost none).
Wiring isn't as easy as it looks! Can you help me figure out how to hook a simple light switch in this bathroom?
Can you give me an idea of why the voltage changes when the adjacent bathroom light switch is turned on with bulbs in the sockets of this adjacent bathroom light switch (which is a two-wire switch in this adjacent bathroom)?
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<%-name%>
• posted on May 27, 2008, 10:47 am
GFCI measure the current in the active and the current in the neutral. If the two currents are the same the GFCI does not trip. If the neutral is connected to another active not the one coming from the GFCI then the current in the neutral coming from the GFCI will be different than the active coming from the GFCI and the GFCI will register a ground fault and not reset. This is called crossed neutrals. The Active and neutral going to the GFCI is the same as that in the House circuits and can be used to supply lights or anything else. But the Active and neutrals leaving the GFCI can only be used with each other and cannot be connected to other actives or neutrals otherwise the GFCI will trip and refuse to reset. As an example a GFCI has a active and neutral connected to a power outlet. Then somebody splices into the neutral and runs it to a light with a different active as soon as the light is turned on the GFCI Trips

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<%-name%>
• posted on May 27, 2008, 1:49 pm
On Tue, 27 May 2008 22:47:09 +1200, Telstra wrote:

Hi Telestra, I must have this "crossed neutrals" situation. I'm still figuring out what you wrote (thanks!!!!!!!)
To get the whole thing back together, before I went to bed last night, I removed the 3-wire (black/white/red) automatic-shutoff switch that caused all this problem in the first place.
Then, I simply tied the two neutrals together and hooked the remaining black and red to the original single pole single throw switch and put it back together waiting for help from here at alt.home.repair.
I added three annotated pictures to the 14-picture set at http://www.flickr.com/photos/27029976@N02/sets/72157605274838278 namely
15. Simplified wiring just before final taping: http://www.flickr.com/photos/27029976@N02/2527299723/in/set-72157605274838278 /
15. Testing with a screwdriver to see the light switch go on: http://www.flickr.com/photos/27029976@N02/2527299815/in/set-72157605274838278 /
17. Putting the original single-pole single-throw switch back on: http://www.flickr.com/photos/27029976@N02/2527299819/in/set-72157605274838278 /
Unfortunately, I must still have crossed neutrals because nothing I did caused the GCFI to go live again.
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<%-name%>
• posted on May 27, 2008, 11:32 am
GFCI can also protect other circuits via load terminals on the back not just the plug outlets and its these wires which probably go to the lights and are connected to a different active or a different neutral or it might be possible the lights have a ground fault ( moisture ) Take the load wire's off of the GFCI'S and see if they reset Mark all of the wires so they can be replaced.

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<%-name%>
• posted on May 27, 2008, 11:51 am

Donna, Thank you for the photos, but there seems to be too many wires and variables to figure it out from a distance. It appears that there are too many wires in some if not all of the electrical boxes. The splices on the pigtails look like they are taped together. The two green twin circuit breakers with the homemade handle tie should not have both circuits going off at the same time. Overall everything looks as though it was done by someone without much code knowledge and experience. The fact that you have odd voltage readings when the light from the other bathroom is on tells me that something may not have been wired correctly from the beginning. Is there any reason why you cannot bring in an electrician to fix this? I think that is what you need to do.
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<%-name%>
• posted on May 27, 2008, 1:54 pm
On Tue, 27 May 2008 07:51:34 -0400, John Grabowski wrote:

Hi John, I do thank you for your help. I may very well need to bring an electrician in. I've never done that before but it sure seems like I'm (almost) stumped on this one. I just hate to let go (can you tell?).
It really irks me when I can't figure out a home repair on my own or with help here. So, I may very well conclude that ... but I first want to understand what is going on.
Bear in mind, the GCFIs were all working so whatever was wired to the two-wire SPST switches before I put the three-wire automatic-shut-off switches in was working properly (albeit I never tested the voltages).
I'm going to mull deeply over the GCFI information from Telestra to see if I can understand it. At the moment, I realize I have "crossed neutrals" but I need to re-read and re-read his explanation before I will know what to do to resolve the problem.
I posted 17 well-annotated pictures of the situation at the slideshow http://www.flickr.com/photos/27029976@N02/sets/72157605274838278/show /
D.
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<%-name%>
• posted on May 27, 2008, 2:04 pm
Donna wrote: ...

...
Uncross them... :)
If you can reconstruct the initial situation, then you should be able to trace which neutral belongs w/ each circuit and wire it appropriately.
--
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<%-name%>
• posted on May 27, 2008, 9:40 pm

Donna, If I was to come over and work on this, my first step would be to identify each conductor's function. Is the white really a neutral or is it carrying juice to feed a switch? What are the red wires for? How does each box and receptacle get fed? Which wires are the feed from the circuit breaker?
Get some numbers or white tape and start labeling everything. Draw a diagram so you see what is happening on paper.
Don't be hard on yourself for not being able to figure it out. It doesn't seem like a normal situation for one thing and for another, everyone has limitations. Even the pros get stumped occasionally.
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<%-name%>
• posted on May 27, 2008, 12:36 pm
At the risk of labouring a point the GFCI has four wires connected to it. Active and neutral from the house supply which goes to the plug receptacles and load wires which go to another protected circuit, Disconnecting these load wires will still leave the plug receptacles LIVE. The varying voltage is due to the fact that you have placed the resistances of the light bulbs in series by mixing up the loop wires to the lights and switches. For example connecting the loop to the next switch to the wire to the Bulb would cause the current to flow in series through both light bulbs. The way the circuit is wired up is Active to light switch joined to active loop wire to next light switch. Neutral to first switch joined to the neutral loop to the next switch. Both switches now have a NEUTRAL and ACTIVE. The two wires from the bulbs are now connected one to the NEUTRAL and one to the SWITCHED ACTIVE.

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<%-name%>
• posted on May 27, 2008, 1:16 pm

A ground fault will trigger it and it may need to be rest [ After you correct the ground fault ]

How are you measuring that voltage? If you are using a modern digital meter, it likely it picking up induced power from wires that are close to each other. If that is it, you would ignore than for this use as it is little more than static electricity. (Note: it is not static electricity however) It also could be a floating neutral, which means you have an existing wiring problem.
All this and your questions and comments leads me to strongly suggest that you hire a professional in this case to weed through all this and make sure everything is properly done. A mistake here can be your last.

--
Joseph Meehan

Dia \'s Muire duit
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<%-name%>
• posted on May 28, 2008, 12:18 am
Making a shrewd guess i would say the installer brought the wires from the GFCI into the backbox of the light switch to connect to other outlets and take advantage of the holes made for the light cables and these wires were never connected to the light. So you have to separate the unprotected circuit from the protected circuit once this has been done the GFCI will reset and the lights will go back to being a simple straightforward job