I recently had a single phase panel with 2 black conducters feeding flouresent lights.When I breakered them 120 volts was comming back in the white conducter.I was told this was normal but never experienced it but when I terminated them to the neutral bar they worked but my neutral bar now has 120 volts to grn (NON-BONDED SUB PANEL).How come the back feed through the white wire doesn't go through the bar back feed into other circiuts and trip there breakers especailly differant phase's.I was told in school it's been a while, single phase doesn't have unbalanced loads unless multi wire circiuts are used.Can someone please explain this to me, Thank You
Return voltage on single phase con.
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jimwalker
Senior Member
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- TAMPA FLORIDA
Re: Return voltage on single phase con.
Does your neutral bar not have a conductor back to the MDP ?
Does your neutral bar not have a conductor back to the MDP ?
- Location
- Windsor, CO NEC: 2017
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- Service Manager
Re: Return voltage on single phase con.
Single phase neutral current is calculated as
Phase A minus Phase B.
So if the sum of the loads on
phase A is 30 amps,
phase B is 20 amps,
then the neutral is carrying 10 amps.
An easy way to remember how it works is like this: As soon as the two phases strike each other, after they pass through a load, cancel each other out.
It works the same on a 14-3 branch circuit as a 4/0 SER run. It happens the same way.
A word to the wise, don't do that.
Single phase neutral current is calculated as
Phase A minus Phase B.
So if the sum of the loads on
phase A is 30 amps,
phase B is 20 amps,
then the neutral is carrying 10 amps.
An easy way to remember how it works is like this: As soon as the two phases strike each other, after they pass through a load, cancel each other out.
It works the same on a 14-3 branch circuit as a 4/0 SER run. It happens the same way.
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