I have a customer with a Siemens Modular Metering service on a strip mall. The tenants have been complaining of flickering lights, GFCI's unable to reset, among other issues. After a little research I found what I believe to be the source of the problem. There is a fused 800A main ahead of three meter stacks which has the correct bonding from what is visible. At the first stack there is a difference that varies between 10 and 20 volts between the EGC and the neutral. Between A,B, and C phases and the EGC is about 122 volts, but to neutral its 108, 118, 145 volts. It seems there is some resistance in the neutral buss connection somehow between the main disconnect and the first meter stack.
This morning I shut the main off and re-tourqed the single bolt joint on the horizontal buss. No change.
Has anyone experienced this? Any options aside from replacement?
