Electrician Talk banner
1 - 20 of 39 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 ·
I am having a very troubling issue on my current job. I have a single phase 400A service entering a greenhouse from central metering at a pole out in the field. Off that service there are 4 x 200A and 1 x 100A sub panels. When any of those main breakers are isolated I can read 110V from any live phase to that particular breaker (which is open at both ends). Anyone ever heard or seen this before? It seems to be effecting the system downstream for the new led lights i have installed.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #4 ·
yes. that is correct, i am testing from the load side of the absolute main 400A breaker to any sub main in the same load centre. With any distribution breaker in the load centre open and their main on the panel down the line open, as well as the neutral disconnected at both points you will read around 108V between that load side of the 400A main (which is on) and any of those wires. Its like reading neutral or ground potential off a wire in thin air.
 

·
Registered
Joined
·
984 Posts
yes. that is correct, i am testing from the load side of the absolute main 400A breaker to any sub main in the same load centre. With any distribution breaker in the load centre open and their main on the panel down the line open, as well as the neutral disconnected at both points you will read around 108V between that load side of the 400A main (which is on) and any of those wires. Its like reading neutral or ground potential off a wire in thin air.
I'm still a little confused on how you are doing this, but in any case, what type of meter are you using? Are you sure it's not ghost voltage?
 

·
Gold Member
Joined
·
312 Posts
When you shut off the main in the sub panel, you are picking up the 'neutral' through a connected load on any of the circuits on that panel. Turn off ALL the breakers in the panel. The voltage will vanish. Also, use a wiggy, for real.
 

·
Registered
Joined
·
984 Posts
When you shut off the main in the sub panel, you are picking up the 'neutral' through a connected load on any of the circuits on that panel. Turn off ALL the breakers in the panel. The voltage will vanish. Also, use a wiggy, for real.
You shouldn't recommend a wiggy. He's testing at the service. A low impedance meter is what he needs, but other than a wiggy.
 

·
Registered
Joined
·
12,167 Posts
I have no idea of what the OP is trying to communicate.
 
  • Like
Reactions: Cow

·
Registered
Joined
·
984 Posts
When you shut off the main in the sub panel, you are picking up the 'neutral' through a connected load on any of the circuits on that panel. Turn off ALL the breakers in the panel. The voltage will vanish. Also, use a wiggy, for real.
The way he describes it, none of the feeders are terminated, and the upstream breaker is open. The voltage would have to be coming from somewhere else.
 
1 - 20 of 39 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top