need help with an odd short circuit

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  #1  
Old 02-14-06, 06:34 PM
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need help with an odd short circuit

I replaced an ordinary single pole dimmer switch with a single pole switch with a convience outlet. the switch and outlet work fine (a 3-wire circuit analyzer confirms the outlet is correct.) But now when I flip a particular light switch on the same circuit breaker (15A) the breaker trips. (the offending switch is just a few feet from the replaced switch). I can turn on every other light on the circuit with no adverse affect. What's going on? thanks!
 
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Old 02-14-06, 06:47 PM
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Exactly what wires do you have in this box, and what is connected to what on the Device?
 
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Old 02-15-06, 08:51 AM
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more info re:short circuit

OK... we're in an older house so the wires are not clearly colorcoded.
The box in question has 8 wires (A,B,C,D,E,F,G,H) entering thru 3 ports (1,2,3). To draw a picture of what I found, put port #1 at nine o'clock, #2 at twelve o'clock, and #3 at six o'clock. moving clockwise from port #1, A,B are in port #1; C,D,E in #2; F,G,H in #3. A and H were pigtailed together. B, D, and G were joined in a wirenut; E and F were joined in a wirenut. AH and C were connected to a dimmer controling an incandescent ceiling light.

using a volt meter, I figured BDG was neutral, EF was ground, and that the dimmer was installed ungrounded on the hot wires AH and C. I installed a leviton combination switch and recepticle (#5225) using AH as the common hot, C on the light switch, and added a pigtail to BDG for neutral, and another pig tail to EF to ground the switch. The switch worked correctly, and my 3-way circuit analyzer showed two yellow lights, indicating a correct outlet.

3 feet away in a bathroom is a box with two switches, controling an incandecent light and a fan, and a dual GFCI outlet. When I flipped either switch the 15A breaker tripped. I did not test the outlets. all other lights on the breaker worked correctly and did not trip the breaker.

This morning I disconnected the switch from my assumed ground EF; and the bathroom switches no longer trip the breaker. the circuit tester shows an open ground on th new outlet, and the ceiling light switch works.

So if this is a safe arrangement Ive solved my problem, but Im still confused about whats going on. (the new outlet will be used for a nitelite)

thanks, hope this was not too much info,
gaelasdad
 
  #4  
Old 02-15-06, 09:12 AM
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I suspect that you do not have ground wires at all. Are these wires from cables, or are they individual wires run in conduit?

I am also concerned that you MIGHT have incorrectly made your connections.

Can you provide details on the wiring of the bathroom receptacle and switches and of the wiring of ALL the lights involved.
 
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Old 02-15-06, 02:47 PM
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more details re: my wiring

I agree that I probably dont have a ground at all.

The wiring is wires in conduit, not cable.

Re: The ceiling light, I checked in the attic and there is only one piece of conduit running to it and it appears that it goes down into the wall above the switch in question. Would this make it a single pole toggle like example 2 at

http://www.doityourself.com/info/h2installswitch.htm?

The other lights on the circuit are all ceiling lights, but were too inaccessible to easily see how they were wired.

The bathroom box is from a later remodel and looks professionally done. It controls vanity lights and a fan/light fixture with romex. the lights work off one switch, and the fan the other. the GFCI outlets both give double yellow (correctly wired) on the circuit analyzer. both the switches and the outlets are grounded to the metal box. The older wires are retro-coded with tape - 2 with black and 1 with white. the fan leads and the fan lite leads are labeled as such.

Id like to ground the new switch but dont think I can get it attached to the back of the box. are there other options?
 
  #6  
Old 02-15-06, 02:55 PM
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Don't attempt to look from the attic. Physically remove the lights and look from below.

Of course you can ground the switch to the back of the box. Go buy a commercial ground wire, packaged in plastic bags of about 10 or 12. They include a screw, and a green wire all set to go.

Is the bathroom on the same circuit as this box you are working on? That would be unusual, especially if the work in the bathroom is new.

Please provide COMPLETE details on the wiring in the bathroom.
 
  #7  
Old 02-15-06, 03:55 PM
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Originally Posted by gaelasdad

Id like to ground the new switch but dont think I can get it attached to the back of the box. are there other options?
You can get grounding clips that clip over the edge of a metal box. You would probably have to chip away plaster or mud to do this.

Otherwise to use the back of the box, depending on how old the box is, it may not be tapped in the back for grounding. In that case get a 10-32 tap and drill set and a grounding pigtail with a screw.
 
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Old 02-15-06, 05:08 PM
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more details re: my wiring

I'll go ahead and ground the switch per one of your suggestions. COMPLETE info on the bathroom wiring and inspecting the ceiling fixtures will probably have to wait till the weekend (my day job is calling).

the bathroom is on the same circuit as the bedroom lite.
 
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