replacing fixture wiring problem


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Old 11-17-08, 08:42 AM
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replacing fixture wiring problem

I decided to replace a ceiling fan ( it was tripping the breaker ,maybe a short and outated anyway) with a light fixture.The box in the ceiling has 3 wire bundles in it each with one black,white, and copper ground wire. The 3 ground wires have a copper clamp around them .My new fixture has one black, white, ground wire. I hooked the fixture black to all 3 black in ceiling,all 3 whites in ceiling and all grounds to fixture ground wire. There is a single switch wall plate that goes to this, and I have it in the off position. When I cut the circuit breaker back on the light on the fixture comes on, if I flip the wall switch into the on position the breaker trips. This breaker also services the bathroom light and exhaust fan. The bathroom light and fan operate normally until I put the bedroom wall switch in the on position thus tripping the breaker. Do I need one less of the wire sets in the ceiling attached to my fixture? Should i have a black with a white? Do I need to run to the home store and grab a tester? Sorry for the length.
Thanks
 
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Old 11-17-08, 09:09 AM
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I haven't followed everything for sure. But you may have one hot wire and two switch legs. To figure this out, you'll need an ohmeter or voltmeter.

First, pull out the wall switch and see what wires are there.

But assuming that my assumptions are correct:

The light fixture should be connected to the switch leg and the white. The whites (neutrals) should be connected together, with a pigtail to the silver terminal on the fixture.

The hot wire should be connected to one switch leg, and the the other switch leg goes to the light.

But don't guess - check it out first with an ohmmeter or voltmeter. If you're not sure how to use a meter to figure this out, best to get some help.
Doug
 
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Old 11-17-08, 09:21 AM
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Did you wire the new light exactly the way the fan was wired? Were there two switches for the fan? How many wires in the switch box? What color wires are hooked to the switch(es)?

What it sounds like is you have two switch loops and power in at the ceiling box. You need to determine which cable is power in. Following assumes you had two switches for the fan. If not post back.

With the breaker off disconnect all wires except ground. Arrange them so they don't touch each other. Turn on the breaker and with an analog multimeter or test light find which cable is hot by carefully testing between white and black. Test all cables. There should be only one. Turn off the breaker.

Put wire-nuts on the black and white of one of the non-power cables. That cable will not be used. Wire-nut the white of the other non-power cable to the black of the power cable. That should leave you with just a black and white to hook to the light.

Note: by code the white wire you hooked to the black power wire should be recolored black or red either with a felt tip pen or tape.
 
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Old 11-17-08, 10:15 AM
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I wasn't the one to take the fan down so I am unsure to which set of wires the blue wire from the fan/light was connected to. I have a single toggle switch on the wall and it has one black and one white and a ground wire.
 
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Old 11-17-08, 11:46 AM
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Originally Posted by kkc66 View Post
I wasn't the one to take the fan down so I am unsure to which set of wires the blue wire from the fan/light was connected to. I have a single toggle switch on the wall and it has one black and one white and a ground wire.
You still need to determine which cable is hot by following my previous instructions. With the wires disconnected and carefully laid out so they don't short and breaker on determine if anything else on the circuit doesn't work.

Now turn the circuit OFF. Set the wall switch to on and check between the black and white of each non power cable. The cable that shows continuity is the cable to the switch and should be connected as I described in my post. Note you may show continuity or near continuity on both cables. If so turn the switch off and one cable should show open. That is the switch cable.

The remaining cable probably provides power to other outlets (receptacle or light). If in your previous test you found those outlets use your multimeter to check.
 
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Old 11-17-08, 01:35 PM
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I borrowed a volt tester (non contact) and tested and it indicated nothing from all sets of wires, it may be a piece of junk, who knows. I was able to get the light on and all receptacles in bedroom as well as the bathroom light and fan but the switch would not cut it on or off (the light remained on with the switch in the off position or on position), but didn't trip the circuit breaker this time. I may need to go purchase a tester. Thanks
 
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Old 11-17-08, 04:20 PM
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No. You need a real voltage tester. Those non-contact testers are fun toys but you need an analog multimeter to really check this out. You could probably get by with a test light. Remember if you get a multimeter you need analog, the one with a hand that shows the reading on a dial not the digital kind with a numeric read out.

(Always turn off breakers when making connections then on briefly to test.)

You could hook the light fixture to each cable to determine which is hot. Next you could disconnect the switch and connect your light to be installed across these two wires. Ignore ground for the test..

Connect the hot cable to one of the non-hot cables. If when you restore power if the devices that weren't working even with the breaker on are working you have found the downstream load cable. The other is for the switch loop. If your light lights up you have found the switch cable.
 
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Old 11-18-08, 07:30 AM
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Success !!!! Thanks for your patience I have marked the wires for future reference.
 
 

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