Objectionable current, would love some input

A

Aelectric

Member
Location
Mass
I have a large lakeside residential project I am on where there is up to 6 volts between equipment grounding conductor and the lake. There is also a couple amps on the grounding electrode conductor. Someone got a little tingle at the lake, and we were called in to investigate. There are (2) services feeding the property (total 4 buildings on the property). The generator, 600 amp main (for house), 400 amp main (for guest house, barn, and entertainment building) are all located next to transformer outside. The service to the house is almost 500' away, the other buildings are between 125'-300' away. The house is the closest to the lake and has a ufer ground that is just under 1 ohm, so that seems good. The equipment ground we are referencing voltage to the lake comes from the house. The odd part, is that as you increase load in the other 3 buildings, that voltage reference to the lake increases. Im not sure how often or even if this is an option but if the transformers neutral isn't perfectly center tapped, would that be enough to trickle some voltage back out to ground at the main service equipment area? Having a hard time figuring out why the 3 smaller building load increases the voltage and current at the main house. I was going to lift the equipment ground that is feeding the main panel in the house and see if that stops the voltage to the lake, identifying that is sending voltage in from main up by the transformer or if its coming from the house. Any other ideas would great and appreciate your thoughts. Thanks
 
Thanks Tom, I was thinking the Neutral VD may be a factor, but being 500' away its tough to test that, like temping another conductor in parallel. There is a little voltage drop on the hots but not bad.

Grounds and Neutrals are all separate at the sub panels. However doing a quick continuity test there is some neutral to ground continuity. We only did this with the one smallest sub panel but took all neutrals off and found 10 or so circuits with at least some continuity. Lutron lighting control, some paddle fans, transformer for alarm panel, etc.
 
Dennis Alwon said:
Is there underground power run anywhere in the area?
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Other then the undergrounds to the buildings on the property, I don't know of any.
ptonsparky said:
A spool or two of # 16 is good enough to parallel the neutral to check for VD. Be careful, current will flow if you are between the two.

Two services. Each service is typical 3 wire with GES at each and about 500' apart?
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The transformer feeds a 600 amp main disco and generator transfer switch near the transformer. then from that main it is 4 wire run to main house 500' away.

The transformer also feeds a second service that is a 400 amp main breaker panel and generator transfer switch, all again next to transformer. Then from the 400 amp main breaker panel there is (2) 125 sub feeds to other buildings and a (1) 200 amp sub feed to another building. All building treated as sub panels/ 4 wire and not bonded. Hope that makes more sense.
 
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