Bathroom light install - too many wires?

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  #1  
Old 07-13-05, 10:06 AM
James G. Blaine
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Bathroom light install - too many wires?

Hi, this web page was very helpful to me in the past, so I will try again.

I am replacing an over-the-vanity light in my bathroom. (house is 14 yrs old)

The new light I purchased has a black, white, and ground wire.

However, I have two sets of wires (three wires each - black, white, and ground) coming out of the outlet box (one switch had controlled the light, and there is also an outlet next to the switch (not controlled by switch)).

FYI, the light that was there before had a plug outlet built in to it.

Not sure if/how I should join these wires for installation?

#1 - When I touch my test light to one set of wires (white and black) the test light goes on, but if I then turn the switch off, the test light actually still stays on.

#2 - Also, when I touch it to the other set of wires (white and black) the test light never goes on.

When I turn off the breaker, both the outlet (next to the light switch) and the wire set #1 both show no test light.

The light worked fine in the prior set up were the two “black” wires were joined (then joined with “black” wire in fixture), the “grounds” were joined, and if I remember correctly one of the “white” wires were joined with a “white” wire in the old fixture, and the other “white” wire was joined with a second “black” wire in the old fixture.

Any help for the new fixture setup would be appreciated.
 
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  #2  
Old 07-13-05, 10:27 AM
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If you attach your new fixture to exactly the same wires as the old fixture was attached to, and you leave all other connections exactly as they were, then this algorithm cannot fail.

If you ripped off the old fixture by disconnecting everything without recording the connections, then we have a lot more work to do.

Can you use the easy fool-proof algorithm?
 
  #3  
Old 07-13-05, 11:23 AM
James G. Blaine
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Thanks for the help, unfortunately, the old fixture had two black wires, and my new fixture only has one black wire, so I cannot hook it up exactly the same way.

I hooked the scenarios up as follows:

Fixture black attached to outlet blacks (two joined) – this was definitely the way it was in the prior hookup.

Scenario – 1: attached Fixture white to one of the outlet white –-> result –-> light stayed on all the time regardless of switch being on or off

Scenario – 2: attached Fixture white to the OTHER outlet white  result  no light at all regardless of switch on or off

Scenario – 3: joined outlet box white wires together  result tripped breaker

It seems that one set of wires has power, but the other wire set does not, but neither is controlled by the light switch.

I probably have hooked up a dozen or so lights over the years, but I cannot figure this one out. How come the light switch seems not to have any affect, but it did work fine on the old fixture. I usually default to the easy fool-proof algorithm, but the light fixtures in this case are different.
 
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Old 07-13-05, 12:47 PM
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Some fixtures come with one black wire and one white wire. Some fixtures come with two of each. Some fixtures come with three of each. Some fixtures come with more. But these differences are immaterial. Just combine all the black wires from the fixture together and treat it as one black fixture wire. And combine all white wires from the fixture and treat it as one white fixture wire.

The above comments don't apply if all the fixture wires are the same color. They only apply to fixtures with an equal number of black and white wires.

Note that for a fixture with two black wires and one white wire, and that includes an integrated receptacle (which is almost never done these days), one of the two black wires is for the light (and is switched) and one of the black wires is for the receptacle (and is unswitched). If replacing such a fixture with a fixture without an integrated receptacle, merely cap off and don't use the unswitched hot wire in the box. If your new light comes on and cannot be turned off by the switch, it's because you connected the unswitched hot to the fixture (maybe in addition to the switched hot, or maybe instead of the switched hot).
 
  #5  
Old 07-13-05, 01:27 PM
James G. Blaine
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Thanks,

What you say makes perfect sense, but no matter what wiring sequence I use I get the light either on or off - but the switch has no affect. I made no changes to the wiring since I took off the old fixture and all breakers are on.
 
  #6  
Old 07-13-05, 01:36 PM
James G. Blaine
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Mmmm, I just joined the two white wires from the outlet, and the two black wires from the outlet, and connected them to the fixture's black and white...and it actually works including the switch. Connecting the outlets white wires caused the breaker to trip the first time I did it, but it seems fine now. Perhaps the trip was just caused by a surge, and did not have anything to do with the wiring?
 
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Old 07-13-05, 01:42 PM
James G. Blaine
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Was wrong, blew breaker again?
 
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Old 07-13-05, 01:44 PM
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Perhaps the trip was just caused by a surge, and did not have anything to do with the wiring?
Yea, right--NOT.

It's time to open up the switch box. Tell us everything you see: all the cables, all the wires, all the connections.
 
  #9  
Old 07-13-05, 01:52 PM
James G. Blaine
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Switch box contains on set of wires with three wires contained (green, white, and ground). Green and white wires are seperately side connected to the switch with two silver colored screws. Ground also attached to ground in switch.
 
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Old 07-13-05, 02:48 PM
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I think there are at least a couple of typos in your post that make it hard to be sure what you're saying. But it seems you have a switch loop. You said "green, white and ground". Do you mean "green, white and black"? Or do you mean something else? Black wires are not ground except in automotive wiring. Is there a bare wire in the box?

If you really only have three wires at the switch box, counting the grounding wire, then you have an unsafe setup and should stop now and not read the following instructions. It may be that somebody converted a grounding wire into a live wire in order to add that receptacle next to the light. This is a really stupid move.
 
  #11  
Old 07-13-05, 03:30 PM
James G. Blaine
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Sorry, the three wires from the outlet are as follows:

1) a "bare ground" wire connected to the ground screw on the switch.
2) a "white wire" connected to a silver side screw
3) a "green wire" connected (on the same side) to another silver side screw

Hope that is a little more clear.

Thanks,
 
  #12  
Old 07-13-05, 04:03 PM
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That makes no sense.

I'm not sure exactly what you mean when you say "outlet". Could you use some other term?

There's no other wire in the switch box? Just bare, green and white? What crazy person wired this house?

Check again.
 
  #13  
Old 07-13-05, 04:13 PM
James G. Blaine
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Those wires are located in a "box" that mounts only the light switch into the wall.

There is also a seperate outlet box about 3 inches from that light switch which has a single recepticle contained in it.

The light switch and the recepticle boxes are seperate.
 
  #14  
Old 07-13-05, 04:23 PM
James G. Blaine
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Sorry about all this confusion, but I guess you could consider that the green wire is actually black. It's looks very, very dark green, but it actually matches the other wires (I had called black) that are used for the fixture.

Sorry again, it's been a long day.
 
  #15  
Old 07-18-05, 12:55 PM
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So James, are you still out there? Do you still need help?
 
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