Tom- I guess this issue has been around as long as I can remember. I would like to comment that if the piping is to be continuous electrically, I would expect to see a jumper for example between the H and C water pipes so the dielectric unions don't isolate a part of the piping system that may become energized and cause an electrucal hazard. I'm sorry, Mr. Plumber, but the law says I must do this. Now for the real world. I don't think there are 5% of the electrical inspectors out there that check this item out and enforce this item. There are so many more items that are not jumped around to maintain continunity that the dielectric union is not even addressed by the electrician. Then we have the non metallic piping and isolated metal plumbing fittings and faucets. In fact since the code has evolved to where the GEC is only permitted to be connected to the water pipe electrode within 5' of where the it enters the building, the only thing that gets inspected for this issue is the water meter and any water filters or water softeners located at the water service entry. Am I off base with this? Good question might be does the plumbing code require dielectric unions? or Does the plumber only install them to prevent the galvanic action?
