nuetral current

[mag100]

I have a 220volt service. I put my ampprobe on the neutral and have approx. 15amps. This is a single phase system. On the other 2 phases I have 3amps to 16amps. I know they are not balanced but what is causing the current on the neutral. The neutral is bonded to ground. Thanks you for any replys. Puzzled!

 

[dpc]

Your 220V single-phase service has two 120V legs. If the loads on each of the 120V legs are perfectly balanced, you have no neutral current. Otherwise, the neutral current is equal to the difference of the two 120V legs. In your case, if you have 16 amps in one and 3 amps in the other, your neutral current would be 13 amps. Your measurement of 15 amps is well within the accuracy of the clamp-on meter.

Current in the neutral is normal and not a concern.

 

[dydt]

hi..
theoretically, you should be getting 16-3=13 amps on the neutral...not 15amps..unless you have some wiring that is not properly wired...like picking up 120v from the ground instead of the neutral...i've seen this wiring esp. in residential houses or old buildings..

dydt

 

[electricpete]

Also a difference in power factor in the loads on the two legs could explain why you don't see exactly 16-3=13.

 

[jbartos]

Suggestion: Using complex numbers (or phasors) the current should summ as follows:
Re[Ineutral] + jIm[Ineutral] + Re[Ihot1] + jIm[Ihot1] + Re[Ihot2] + jIm[Ihot2] = 0 + j0, in amps
A power factor meter could help in this situation.