Both wires hot to ground 0 together 120v

240v

Member
Location
Cincinnati Ohio
Occupation
Maintenance electrician
My hot wire and neutral test 115v by themselves to ground but test neutral to hot it's also tripping two breakers in the same panel both on the same side. It's a huge place and the conduit is in the ceiling and I can't get to them to trace them back to their source. What can be going on and is there a way to trace the wires without shutting breakers off
 

240v

Member
Location
Cincinnati Ohio
Occupation
Maintenance electrician
Can you please explain each of these complaints with more detail?
Ok the hot and the neutral if you put your meter on the hot and the neutral your meter reads 0v but if you test hot to ground you get 115v and if you test the neutral to ground you also get 115v. The two breakers tripping are on a different line going to a 110v 10amp motor for a roll dock door when I put power to it it trips two different breakers on the same side of the bus I think it's probably the wiring over the door it's bad I'm going to replace it tomorrow and try it again. I checked all the wiring to the control I checked all the relays switches windings that all checked out I'm more concerned about the hot and neutral situation it's almost like the neutral is wired to a different phase than the hot and they are cancelling each other out but that's why I'm asking
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Ok the hot and the neutral if you put your meter on the hot and the neutral your meter reads 0v but if you test hot to ground you get 115v and if you test the neutral to ground you also get 115v.
It sounds like your neutral is energized.

I need to know what you're getting these readings from, panel, receptacle, etc.

The two breakers tripping are on a different line going to a 110v 10amp motor for a roll dock door when I put power to it it trips two different breakers on the same side of the bus
That sounds like two breakers feeding the same wire.

Are these both in the same place? Maybe you have a bad shared neutral, perhaps in a feeder.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
Please provide all of the possible voltage readings. It doesn't take much more time. But can help answer some questions.
L1-L2
L1-N
L2-N
L1-G
L2-G
N-G

Do the breakers stay on when only one at a time?
 

240v

Member
Location
Cincinnati Ohio
Occupation
Maintenance electrician
I haven't even traced the wires back to the source yet I was just trying to tie in to get electric down the line and found this mess. This is supposed to be 120v single phase but two separate lines 115v each and 0v together makes me wonder what's going on. Sounds like I'm just going to have to trace it back to the source I was really hoping to avoid that. There's six separate 120v breaker boxes seven if you count the new part of the building it's hundreds of feet apart 40 foot ceilings and whoever ran this wire went back and forth between junction boxes with separate conduit all for one circuit it's unbelievable
 

TwoBlocked

Senior Member
Location
Bradford County, PA
Occupation
Industrial Electrician
I haven't even traced the wires back to the source yet I was just trying to tie in to get electric down the line and found this mess. This is supposed to be 120v single phase but two separate lines 115v each and 0v together makes me wonder what's going on. Sounds like I'm just going to have to trace it back to the source I was really hoping to avoid that. There's six separate 120v breaker boxes seven if you count the new part of the building it's hundreds of feet apart 40 foot ceilings and whoever ran this wire went back and forth between junction boxes with separate conduit all for one circuit it's unbelievable
I feel your pain! If things have been cobbled for too long, the best answer is to run new conduit and wire so you KNOW what you have. And watch out for someone using the ground as a neutral and a white as a hot because they ran out of conductors! If things have been cobbled, don't trust the colors.
 

kwired

Electron manager
Location
NE Nebraska
The voltage on neutral to ground is indicative of the neutral being open or loose at the panel.
Was my first thought.

To OP: if that is the case the "hot" is feeding through the load but the neutral is open before it gets back to the source, this leaves the neutral at ~120 volts to ground because there is no voltage drop across the load if no current is flowing.
 
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