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Old 03-25-2019, 08:31 PM   #1
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Default Why am I getting voltage where I didn’t expect it?

So I just wired up a ceiling fan/light, I ran 12-3 wire to put the fan on a separate switch than the light. I ran 12-2 wire for incoming power and pigtailed the hot wire to both the bottom side of the switches and then the 12-3 black to the light and red to the fan. I haven’t actually mounted the fan yet to see if it worked, but I wanted to test it first and my induction tester sensed both wires hot with only one switch on. So I put my multi meter on the wires and when I have only one switch on one wire reads 120V like expected and the other wire reads around 70V which is totally unexpected to me. Any ideas? What am I missing? I’m a first year apprentice.
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Old 03-25-2019, 08:46 PM   #2
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Sounds like a ghost voltage to me, use a wiggy or a lncandescent bulb and a weatherproof socket to test it out. A DMM has to high of an impedance to be reliable.
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Old 03-25-2019, 08:58 PM   #3
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It is my cheapo DMM from harbor freight.
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Old 03-25-2019, 09:05 PM   #4
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Old 03-25-2019, 09:20 PM   #5
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Could just be an induced voltage from the switch leg being on. When both switches are off you have 0v? I’m sure it would disappear if you attached a load to the one switch leg.
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Old 03-25-2019, 09:35 PM   #6
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The ultimate test: Cut the cable with your brand new strippers. That'l tell you if you got's real volts or not.............
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Old 03-25-2019, 11:11 PM   #7
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The ultimate test: Cut the cable with your brand new strippers. That'l tell you if you got's real volts or not.............
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Old 03-26-2019, 06:31 AM   #8
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Do PUCO's high voltage lines go over your house?
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Old 03-26-2019, 08:39 AM   #9
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Where's your wiggys?
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Old 03-26-2019, 09:07 AM   #10
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What your seeing is called ghost voltage. That is why everyone is telling you to use a wiggy (solenoid type that puts a load on) or load it with a light bulb. A low z setting on a meter is the same thing. This I a good learning experience, don't trust just a voltage reading when troubleshooting.
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Old 03-26-2019, 11:04 AM   #11
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Thanks for explanation!
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Old 03-26-2019, 12:00 PM   #12
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The ultimate test: Cut the cable with your brand new strippers. That'l tell you if you got's real volts or not.............




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Old 03-26-2019, 12:02 PM   #13
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Thanks for explanation!
Whenever your safety is involved use a tester that provides a load on the circuit.
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Old 03-26-2019, 12:49 PM   #14
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Turn it off and switch the other one on...what reading do you get?



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Old 03-26-2019, 03:08 PM   #15
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It’s definitely a ghost voltage, I just never thought that I would see that high of a ghost voltage on 120V. What is the highest ghost voltage you all have seen on a 120V circuit?
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Old 03-26-2019, 04:59 PM   #16
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600 volts. To be fair, it was right next to a cemetery.
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Old 03-27-2019, 09:00 AM   #17
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Originally Posted by Kmurd View Post
Itís definitely a ghost voltage, I just never thought that I would see that high of a ghost voltage on 120V. What is the highest ghost voltage you all have seen on a 120V circuit?


Up to 70v on some older homes


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Old 03-27-2019, 11:17 AM   #18
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If you know you wired it correctly just put up the damn fan and turn it on. Guess what, it works...


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Old 03-27-2019, 12:15 PM   #19
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Thanks, I will when I’m good and ready to.
So at first it surprised me enough to second guess myself, and then I was curious enough to ask more about it.
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Old 03-27-2019, 06:51 PM   #20
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Default Ghost Voltages

I am in an area with a LOT of 50-60 yo homes. It is easier to count the number of homes without ghost voltage. The real issue is that we can NOT TRUST our wands to tell us anything, they flash and ring constantly even when there is no actual voltage.

The WORST part is finding the right breaker to turn off. Pretty hard when a "dead" circuit rings your wand or shows 90 volts with a meter, my wiggy is not meant to hold a circuit for long (I don't want to destroy it) Yep, happens all the time here.

This week we had a remodel that was driving me crazy, found out that there are at least 6 circuits abandoned in the ceiling when we tore out the rock and soffits. Each of those circuits were abandoned from the breaker but stayed on the neutral and ground. Yup, I get voltages on my wand at each of them. I see voltage with my meter (sometimes surprising voltages) but nothing with my wiggy, not even a click.

The real issue is that it takes my time no matter what.
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