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Mike G.
Mike G., Master Electrician
Category: Electrical
Satisfied Customers: 7491
Experience:  Proven Professional 48 years Experience
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Is there anyway to prove that there is a backfeed coming

Customer Question

Hi is there anyway to prove that there is a backfeed coming from a borrowed neutral prior to disconnecting it? Or does it only become live once disconnected??
JA: I'll do all I can to help. Tell me a bit more about what's going on so we can help you best.
Customer: It was an incident that happened and we are trying to prevent it from happening again. we just need to know prior to disconnection can you prove a back feed on a borrowed neutral exists?
JA: Is there anything else important you think the Electrician should know?
Customer: No
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Electrician about your situation and then connect you two.
Submitted: 1 year ago.
Category: Electrical
Expert:  Mike G. replied 1 year ago.
Hi, I'm Mike G and I'll be assisting you. Any neutral will show voltage when disconnected if the is a load on the circuit from outlets after it.
Customer: replied 1 year ago.
The answer doesn't provide clarity. If we prove dead at the source and also the destination if there is a back feed (borrowed neutral) can this be detected prior to disconnecting or is it only upon disconnection you will detect voltage. For example take a 3phase Distribution Board. I isolate a 3phase circuit as I wish to remove the circuit from the DB. The circuit has been proved dead but upon disconnection it suddenly comes live due to the back feed. Is it only on disconnection we notice this?
Expert:  Mike G. replied 1 year ago.
A 3 phase 4 wire circuit will have current on the neutral all the time. Other than that a neutral will read voltage to ground when there is a load after the point being tested if not connected. The wire being disconnected and the hot through the load is looking to complete the circuit, is why.