This is not a code issue but I don't know who to ask. I am a small electrical contractor in Houston, TX. In my 46 years in the trade I haven't done much residential work, just for friends and family.
I recently built a second residence in an un-incorporated area in the Texas hill country between Austin and San Antonio. There is no inspection of any kind. I had a builder build the house but did my own electrical. The builder and all the subconractors did an excellent job. I drove a ground rod on my 225 amp service and bonded to the cold water pipe. The water pipe is PVC up to the house then copper in the fill under the slab. The hot water pipes are copper and run in the slab also except on the second floor. I was even planning to bond the cold water to the hot water at the electric hot water heater. A friend of mine up there got shocked in the shower when the hot water heater element went out.
In that area of Texas builders use a real fine crushed limestone for fill since there is no bank sand available. The builder jumped on me for bonding to the cold water pipe, that it caused electrolysis. I asked the plumber his opinion and he said he thought it did too.
I told them I thought a water pipe ran in this semi-moist (maybe) limestone fill would not be able to make up its mind whether it was at ground potential or not and if I bonded it to ground I thought there would be less chance of elctrolysis than if I didn't. They are not convinced but I am still bonded to the cold water pipe.
I don't know of any experts on this subject. Can you either advise or recommend someone to talk to?
Tom Fitch
