This will be handled by an electrician, but I wanted to get info on what's permissible as my first stab at talking to an electrician led to a conclusion that seems disallowed and unsafe (entirely isolated ground system for an antenna).
We have a 1950's house with the service entrance at a back corner and the water main entrance near the center of the front of the house. It looks like the primary grounding for this house is a 4 gauge conductor from the panel through conduit buried in the slab and bonded to the water main a foot or so after it enters the house.
A new antenna connection penetrates the house near the water main and has a lightning arrester in-line, currently connected to nothing.
- Does it make sense that that water main (about 50-80 feet away from the main panel) is the primary GEC for the house?
How to bond the lightning arrester bus bar:
New ground rod outside, > 16 feet from water main, bonded via approved clamp to water main outside
New ground rod outside, > 16 feet from water main, with 4 ga conductor running inside and then about 10 feet and also clamped separately to water main near entrance.
or #2/#3 without the new ground rod.
The first electrician who I talked to said "just drive a ground rod, at least 8 feet, and call it a day," but didn't have anything to say about tying it to the house electrical grounding system.