with three options for grounding the unmetered leg of a 3 phase service, ground rod, cold water or building, which is the best and safest??????? thanks--dave
You don't have a choice. If there is a metal underground water piping system, you must use it. If there is effectively grounded building steel you must use it. If they both exist, you must use them both. If you have only the water pipe, you must supplement it with a made electrode and comply with the 25 ohm rule in 250.56 for the made electrode. Don
