Our company was called to trouble shoot a problem with what appears to be return current (neutral current) on the equipment grounds from the branch circuits. Upon inspection of the panel we discovered that if we removed the grounds from the ground bar with the branch circuit connected we have what appears to be return current present on the ground wires. If we then also lift the neutral wire that voltage increases substantially. The readings we get are as follows on the EGC for the given circuit:
Kitchen receptacles, 120V
Bathroom, 70V with neutral disconnected and 34.5V connected
Upstairs lights, 102V with neut disconnected and 46V connected
Lights downstairs, 80.6V neut. disconnected and 41.6V connected
upstairs receptacles, 112V neut. disconnected and 55.4V connected
downstairs receptacles, 77V neut. disconnected and 36.5V connected
Refer, 76V neut. disconnected and 38.9V connected
Of coarse this would lead you to believe that the equipment gounding conductor and the neutrals have been tied together somewhere, except the only circuit that shows continuity between the EGC and neutral is the kitchen receptacles, nothing else rings out. Also, this house had a direct hit with lightning about one year ago, we live in an area that gets very little lightning and so I have little experience with those consequences. Any ideas on what to do next to correct problem? Thanks!
Kitchen receptacles, 120V
Bathroom, 70V with neutral disconnected and 34.5V connected
Upstairs lights, 102V with neut disconnected and 46V connected
Lights downstairs, 80.6V neut. disconnected and 41.6V connected
upstairs receptacles, 112V neut. disconnected and 55.4V connected
downstairs receptacles, 77V neut. disconnected and 36.5V connected
Refer, 76V neut. disconnected and 38.9V connected
Of coarse this would lead you to believe that the equipment gounding conductor and the neutrals have been tied together somewhere, except the only circuit that shows continuity between the EGC and neutral is the kitchen receptacles, nothing else rings out. Also, this house had a direct hit with lightning about one year ago, we live in an area that gets very little lightning and so I have little experience with those consequences. Any ideas on what to do next to correct problem? Thanks!