I'm replacing a failed electric water heater that was connected with 10-2 romex wire without ground. The inspector says that since it was that way before it is grandfathered in but it seems to me that it would be safer if it was grounded. Immediately above the water heater there is a large (#6 or #8) solid wire clamped to the cold water pipe which runs back to the grounding bar on the main panel. Is it a good idea to connect a wire from the ground screw on the water heater to the clamp on the water pipe? If so what gauge wire? If not, what should I do? Just be happy that the inspector said it was grandfathered? Run a new 10-2 with ground all the way back to the panel?
Thanks in advance for advice on this.
Ideally, that ground should NEVER conduct any electricity, but to be safe a #10 or # 12 ground wire will be sufficient connected to the existing ground clamp.
Licensed residential and commercial plumber