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Old 03-06-2012, 10:22 AM   #1
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Stray electrical voltage...what gives


Quick question. I have a ceiling light in my hallway...that stopped working...took the screws out and pulled down the fixture, after turning off the CB and checking with a voltage detector, of course. Turned the power back on...turned on the wall switch...found power on the black lead going to the fixture...okay got power.

Turned off the fixture wall switch and, being ever cautious, checked the black wire to the fixture again...hmmm...still has power...have to turn off the breaker to kill the power to the black wire going to the fixture.

Don't tell me that they wired the wall switch in the neutral line...instead of the hot line. Is that what they did? If so, what's the fix.

Anyways, was going to replace the ceiling light fixture with a new one. It's older than snow and in need of being replaced.

Just looking for some help from those who know...cause I sure don't.

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Old 03-06-2012, 10:29 AM   #2
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Stray electrical voltage...what gives


It's possible the switch in the wall is just switching the white wire. Or your voltage sniffer is giving false readings. You can check the switch out by removing it.

Also you should always do this work with the breaker off with a note at the breaker panel not to turn it back on.

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Old 03-06-2012, 10:47 AM   #3
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Stray electrical voltage...what gives


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It's possible the switch in the wall is just switching the white wire. Or your voltage sniffer is giving false readings. You can check the switch out by removing it. Also you should always do this work with the breaker off with a note at the breaker panel not to turn it back on.
Yep for sure about the breaker and note...have had the shocking experience before...more than once...lol...so no longer take chances.

Circuit tester is working fine...checked against a known hot circuit. It beeps like crazy...there is definitely 120 V/ac there.

If they have placed a switch in the neutral...white wire...how do I fix that. I don't like that the neutral is switched...that leaves the hot wire to electrocute anyone or thing that grounds it...as it's always hot. I know better than to do this. Just don't know how to fix it.
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Old 03-06-2012, 10:58 AM   #4
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Stray electrical voltage...what gives


First of all, don't rely on a voltage tester to give accurate readings. Use a multimeter if you want to know for sure if there is any actual voltage in the line.

Secondly, how many wires enter your fixture box, and how many enter your switch box? And what connections are being made at the switch?
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Old 03-06-2012, 11:31 AM   #5
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First of all, don't rely on a voltage tester to give accurate readings. Use a multimeter if you want to know for sure if there is any actual voltage in the line.

Secondly, how many wires enter your fixture box, and how many enter your switch box? And what connections are being made at the switch?
You're absolutely right...voltage checkers can't tell what the voltage level is, just whether or not there's voltage...misspoke there.

There is a gob of wires in the fixture box...it's in a circuit. I think I have 5 light's in all parts of the house on CB14...and this is one of them. I checked the wire hanging down and connected to the fixture.

I'll check the switch and get back to you...

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Old 03-06-2012, 11:55 AM   #6
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Stray electrical voltage...what gives


Could the branch circuit be double fed from the same phase in the panel? That would be a problem in need of fixing.
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Old 03-06-2012, 01:26 PM   #7
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Stray electrical voltage...what gives


Okay...back again...with pictures. I think this is original wiring from 1954 when the house was built. So, it's pretty old. Then again, the tape doesn't look 58 years old.

This is my junction box where my hallway light fixture is installed. Notice the three black wires with the white wire all hooked together. And, no wiring nuts.
Below that is three white wires hooked together with the white lead for the light fixture extending from the end, not visible in this photo. I can see at least two 14-2's coming into the box.



This is my light switch for the hallway light. Is this normal for a switch?


Thanks for taking time to answer my questions.

Last edited by Ed911; 03-06-2012 at 01:29 PM.
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Old 03-06-2012, 01:30 PM   #8
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Stray electrical voltage...what gives


You have power at the light fixture and a switch leg that turns the light on and off. I would replace tape with wire nuts and get rid of the back stabbed switch and wrap it around the screws.
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Old 03-06-2012, 01:37 PM   #9
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Stray electrical voltage...what gives


Firstly, you should probably turn the power off and take the electrical tape off of the connections, and use proper wire nuts.

Secondly, yes everything looks alright. The three blacks and the white connected together are the constant power, with the white going to the switch. The black connected to the light fixture is the other wire connected the switch.

You said that the black connected to the fixture has power even with the switch turned off. So, where exactly did you test for voltage? And again, the voltage tester you’re using is notorious for giving false positive readings.
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Old 03-06-2012, 01:40 PM   #10
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Stray electrical voltage...what gives


I'll get my meter and measure since I'm going to take the wire nuts off anyways. Let you know in a few minutes.

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Old 03-06-2012, 01:44 PM   #11
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Just don't forget what one is the switch leg.
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Old 03-06-2012, 02:00 PM   #12
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Stray electrical voltage...what gives


Okay...between the white and black that went to light fixture, 119 VAC with the switch on.

However, with the switch off, I still measure 41.9 VAC between the white and black wires running to the fixture.

Note that the wire nuts and fixture were removed for this test. So, I was on bare wires.

Hmmm. Puzzles me.

What do you think. Am I picking up stray voltage because there are so many hot wires in the box? Or, bad switch?

Last edited by Ed911; 03-06-2012 at 02:03 PM.
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Old 03-06-2012, 02:48 PM   #13
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Firstly, you should probably turn the power off and take the electrical tape off of the connections, and use proper wire nuts.

Secondly, yes everything looks alright. The three blacks and the white connected together are the constant power, with the white going to the switch. The black connected to the light fixture is the other wire connected the switch.

You said that the black connected to the fixture has power even with the switch turned off. So, where exactly did you test for voltage? And again, the voltage tester you’re using is notorious for giving false positive readings.
They way the you described the wiring makes perfect sense. By running the white wire to the power side of the switch, you leave the black wire can be used for the power side of the light fixture...cool.

Thanks.

Last edited by Ed911; 03-06-2012 at 03:32 PM.
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Old 03-06-2012, 10:07 PM   #14
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Stray electrical voltage...what gives


Quote:
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Okay...between the white and black that went to light fixture, 119 VAC with the switch on.

However, with the switch off, I still measure 41.9 VAC between the white and black wires running to the fixture.

Note that the wire nuts and fixture were removed for this test. So, I was on bare wires.

Hmmm. Puzzles me.

What do you think. Am I picking up stray voltage because there are so many hot wires in the box? Or, bad switch?
Neither. You are reading what is commonly called inductive or "fantom" voltage. You have a hot wire (the white) in the same cable assembly as the black wire (connected to nothing) and it will pick up some inductive voltage, which can be read by a high-impedance input digital meter.

Re-connect the fixture, put a bulb in it, and try your tests again. Bet ya you will read -0- volts with a load imposed on the lone black wire.
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Old 03-07-2012, 10:48 AM   #15
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Neither. You are reading what is commonly called inductive or "phantom" voltage. You have a hot wire (the white) in the same cable assembly as the black wire (connected to nothing) and it will pick up some inductive voltage, which can be read by a high-impedance input digital meter.

Re-connect the fixture, put a bulb in it, and try your tests again. Bet ya you will read -0- volts with a load imposed on the lone black wire.
Thanks, did that and you are correct. One never knows...just wanted to be safe. The fixture was very old...the wire nuts and fixture socket were ceramic.
I did wire nut everything with new wire nuts...

Thanks for everything guys...I really appreciate the help I got here.

Ed

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Last edited by Ed911; 03-07-2012 at 10:51 AM.
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