GEC

[Daylight]

I have been callec to investigate an issue with pitted water pipes.$15,000 dollars worth of plumbing repairs.3 seperate apt. buildings each with a 3ph 4w 400a service 1 4" water main feeds all three buildings.There is no ground wire run to the 4" where it enters the building,yet at each service there is a #8 solid run to a ground rod and a 1/0 run to the nearest 2" cold water pipe.Should all 3 service ground conductors be tapped together and run to the 4" main and could the grounding and bonding structure be effecting the copper tubing?

 

[hurk27]

Re: GEC

I would have the utility check all their neutral connections at the pole, transformer. Sounds like it could be a bad connection on either side of the transformer, primary or secondary. The GEC to the rod should be a #6 but I wouldn't remove any GEC's off the water pipes until the utility makes sure the primary neutral is good. Use a clamp on amp meter first on the water pipe GEC then on the rod GEC Cheak all of them and see if one has a higher reading (if any at all)