Odd switch wiring, please advise


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Old 08-07-16, 10:06 AM
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Odd switch wiring, please advise

Just bought a house that had several of the lights/ceiling fans removed so I thought that they may have sentimental value to the previous owner. The house passed inspection.

One room has a ceiling fan that stays on no matter the switch position and have found out the following.

The switch and the light fixture seem to be on different breakers- I can shut off power to the light using one breaker but the wall switch has power. The switch will stay powered until a second breaker is disconnected.

The voltages I found on the light are as follows.

Hot to GND (SWITCH OFF) 21V
Hot to GND (SWITCH ON) 124V
HOT TO NEUT (SWITCH OFF) 77V
HOT TO NEUT (SWITCH ON) 0V
GND TO NEUT (SWITCH OFF) 124v
GND TO NEUT (SWITCH ON) 124v

I plan on getting an electrician this week but I was seeking advice on anything I can do that may be a quick fix that I can do. I do work in the electrical field, but in the industrial controls side (plc programming, some electrical troubleshooting, etc.)
 
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Old 08-07-16, 10:15 AM
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Welcome to the forums! I'll address your voltage findings. First, in a switch, there is no neutral, only black wires, unless power enters the switch first. There should be a piece of black tape around the end of the white wire indicating it is, in reality, a black wire. That is, depending on the electrician who wired the house. It will help us, too, for you to remove the power to the light/switch and remove the switch and post pictures of the switch and the light/fan fixture wiring.

You should be getting 120 volts from the hot wire to the ground no matter what position the switch is in. Once you turn on the switch, power will run through it and you will get 120 volts from either screw to ground.

We'll wait on pictures.

It appears you are using a digital volt meter, and are receiving phantom voltages for your effort. Readings using an analog ($10 or so at HD) will give better readings.
 
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Old 08-07-16, 10:26 AM
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I'm a little confused..... the lights/fans were removed and you installed new ones ?
The house will pass inspection as long as the box is covered.... even with a blank plate.

You have to identify how the two circuits are used before the voltages will help.
It sounds like you have a switch loop to the switch where the voltage is sent to the light and a two wire cable is used to switch it.

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To add to Larry's reply.... http://www.doityourself.com/forum/el...-pictures.html
 
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Old 08-07-16, 10:31 AM
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You say that the switch does not turn off the fan. You also said the fan and switch are on separate circuits. That tells me that that is not the switch for that fixture. I would check every outlet in the room (check both the upper and lower socket at each outlet). I suspect the switch may be controlling an outlet.
 
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Old 08-07-16, 10:38 AM
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Thank you for the welcome.

For clarification there are 5 ceiling/lights & switches in questions- 4 rooms have plastic covers where the fan would go with similar voltages at the (assumed) switches. There was a ceiling fan/light in 1 room that stays on no matter the switch position with similar voltages of the other 4.

The room with the existing fan and the 1 room I was going to throw a fan/light have constant power unless a breaker is shut off.

These photos are of the 1st room I was going to put a fan in. I also threw in a couple of the circuit breaker panel. The breakers that effect the switch is "Bedrooms #2 and #3" and the breaker that will kill power to the light assembly is "GFI"Name:  IMG_6138[1].jpg
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Old 08-07-16, 10:42 AM
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There is only 1 switch in that room. Its confusing, and makes no sense.
 
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Old 08-07-16, 10:43 AM
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A couple of issues here.

That doesn't look like a box rated to hang a ceiling fan on.
The cable at the switch and the cable at that box are not the same cable.
A circuit needs power to work.
 
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Old 08-07-16, 10:54 AM
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A couple of issues here.

That doesn't look like a box rated to hang a ceiling fan on.
The cable at the switch and the cable at that box are not the same cable.
A circuit needs power to work.
Thanks for the information on the box, I will do more research into that.
I now understand that is not the same cable, going through the switch should just be the hot.

There was a graphic in this thread showing that the power may be first brought in to the light fixture and then the hot will be inline with the hot thus switching on and off the power. It seems like this is not the situation in this house because when I turn off the circuit to the fan the switch still has power.

Can there be a backfeed of voltage from miswired switch or receptacle?
 
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Old 08-07-16, 11:00 AM
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In your two posted pictures.... each box has only one cable in it. If the cable went from the switch to the light.... that would be a switch loop BUT there would be no power connection.

Those cables connect to a different location.... not to each other.
 
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Old 08-07-16, 11:05 AM
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In your two posted pictures.... each box has only one cable in it. If the cable went from the switch to the light.... that would be a switch loop BUT there would be no power connection.

Those cables connect to a different location.... not to each other.
I just looked up some diagrams and you are exactly right. I will look in the wall for another set of wires. There has to be another set somewhere...

Thanks for the help.
 
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Old 08-07-16, 11:14 AM
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Switch on most likely turns on a wall outlet for a lamp and fan box is not switched. Just a guess.
 
 

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