120V across conductors

working4living

New member
Location
lafayette,in
Hello everyone! Newbie here. I have a question and please accept my apology if this is the wrong section for this but question is this......also an apprentice so wanting to learn.

Had friends parents call me and wanted me to look at the power to the garage............
here is the setup

#10 coming from main panel in the house to a panel in shed
then #12 goes from panel in shed to garage
when i pull off the red wire and the black is still hot on breaker i get 120V across the black and the red??
I have told them we will need someone with more experience of course but my question is............what the heck is going on there???
is a neutral contacting the red somewhere between the panel and the garage???

Thank you in advance!!
 

ActionDave

Moderator
Staff member
Location
Durango, CO, 10 h 20 min without traffic from wing
Occupation
wire pulling grunt
Had friends parents call me and wanted me to look at the power to the garage..........
This will continue to happen.
I have told them we will need someone with more experience of course
Good.
but my question is............what the heck is going on there???
is a neutral contacting the red somewhere between the panel and the garage???
What is the reason you were asked to check out the garage?
Where are you checking the voltage, at the shed or the garage?
Thank you in advance!!
Your welcome and welcome aboard.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
Welcome to the forum. I agree someone with more experience but with a multi wire branch circuit you may have voltage on the disconnected wire simply because it is reading through elements or something else that is energized.
 

Strathead

Senior Member
Hello everyone! Newbie here. I have a question and please accept my apology if this is the wrong section for this but question is this......also an apprentice so wanting to learn.

Had friends parents call me and wanted me to look at the power to the garage............
here is the setup

#10 coming from main panel in the house to a panel in shed
then #12 goes from panel in shed to garage
when i pull off the red wire and the black is still hot on breaker i get 120V across the black and the red??
I have told them we will need someone with more experience of course but my question is............what the heck is going on there???
is a neutral contacting the red somewhere between the panel and the garage???

Thank you in advance!!
First off welcome here! One of the first things you should learn is that electricity is not THAT much of a mystery. You didn't really give enough information for us to know for sure what the problem is. Regardless though, here is my input. the KISS principle (keep is simple stupid) Make this a simple puzzle, like a video game. Get a diagram of a 120/240 volt sinlge phase transformer so you can see what I refer to. Starting at the tranformer on the black lead, if you are ONE electron your goal is to leave the transformer and find a path back to your starting point. You can do this on either the red lead or the white lead, because as you should notice, they connect to the black terminal inside the transformer. As silly as this sounds, all troubleshooting boils down to this one principle. When your electron gets stopped by and "open" be it a switch, a break or in your case a lifted wire, that is one place you can read a voltage difference. So, if you lift the red wire, and you have a motor somewhere that runs on the black and red with no white, the electron leaves the panel, runs along the wire. Comes to the switch to turn the motor on, goes through the switch (when it is on) through the motor, back to the switch on the red wire, through thte switch, along the wire, and oops, roadblock, I can't go any further, because the red wire is not connected, I go back but there is no other path. Wait, someone just hooked up a meter, I run through the meter, through the breaker back to the transformer and I am home. The meter registered my run through it.

It is a simple as that! What voltage you get tells us much more information, but that is for a deeper theory day. I firmly believe that if you take the above seriously, you will be able to troubleshoot anything!
 

teufelhounden91

Senior Member
Location
Austin, TX, USA
Continuity?

Continuity?

Most of the time when you read voltage on a wire that is not supposed to have voltage on it, there is a hot wire making contact with it somewhere. If you have a multimeter (get one if you dont, every electrician needs one...even though they're expensive), you can check for continuity with the power off in a few different spots.

What we need to know is what happened to have them call you in the first place? Did a breaker trip? Did a light turn off when they turned a switch on? What happened?

Next we need to know what you did to check the problem out. Telling us that "the red wire" is disconnected doesn't mean anything to us. "The red wire can be a 12/3 red conductor, or the red wire coming into the panel, or a red wire coming off of a motor. What red wire?

I'll be happy to follow through with you on this if you get me some more detailed info.

Welcome to the trade, you'll fall in love with it quickly =)
 
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