Grounding conductor

I found a grounding conductor clamped downstream of an isolation valve and pressure reducing valve on a copper plumbing supply. The plumbing supply continued outside to an exterior hose bib. I traced the grounding conductor and it went through the crawlspace foundation to a grounding electrode burried outside the front door of the house. I am assuming there is a splice to the service panel bond with the neutral in the wall. Any idea why this grounding conductor would be attached downstream on a copper supply plumbing? Why is it leading into the direction of a ground electrode buried in the dirt outside?


Maybe the isolation valve and/or pressure reducing valve was breaking the electrical continuity of the pipe and somebody wanted to make sure the pipe was solidly bonded to ground.

Maybe the dwelling has plastic water supplies to the dwelling and they are simply bonding the water line in compliance with 250.104 and has nothing to do with the grounding electrode system at all.

Yes, the service water supply is plastic. I am not familiar with bonding the water line in compliance with 250.104. Do you know where I can get some information about it? Thanks.

That is what it seems to me.
I see, and do, this every day. Only a small portion of the homes around here are on town water will metallic feed piping.

If the water line coming in is plastic, and the home’s pipework is metallic, you can bond the metallic pipework anyplace that pleases you most. It must be bonded, however, and catching it on the way out to the rods was apparently the easiest thing to do in that particular case.

This might be a better resource for you in BC:

**250.104(A)(1) - ENJOY

(A) Metal Water Piping. **The metal water piping system
shall be bonded as required in (A)(1), (A)(2), or (A)(3) of
this section. The bonding jumper(s) shall be installed in
accordance with 250.64(A), (B), and (E). The points of
attachment of the bonding jumper(s) shall be accessible.

**(1) General. **Metal water piping system(s) installed in or attached
to a building or structure shall be bonded to the service
equipment enclosure, the grounded conductor at the service,
the grounding electrode conductor where of sufficient size, or
to the one or more grounding electrodes used. The bonding
jumper(s) shall be sized in accordance with Table 250.66 except
as permitted in 250.104(A)(2) and (A)(3).

I had a electrician call me the other day over an inspection I did recently. Seems as if the supply from the street was plastic and the plumbing was mixed plastic, copper, galvanized. He asked me if I expected that he should ground each piece of metal piping. The meterbase had a ground rod by the way. I welcome comments

It is our/your/their job to determine just exactly what a piping “system” is.
IMO a few short sections of copper pipe do NOT a “system” make.