Using the water service as a grounding electrode

[steve66]

The code requires the water service to be used as a grounding electrode for the electric service when available.

What happens when the water service is a really far away from the electric service? Is it required to run a ground wire clear across the building? Or can the water service be connected to the building steel, and then connect the steel to the service ground?

And does the wire have to be sized per table 250.66? It doesn't look like there is a exception for a water pipe like there is for rod, pipe, and plate electrodes that reduces the wire size to a #6.

 

[infinity]

Yes you can use the building steel as part of the GEC path for the water pipe electrode, you would need to size your bonding jumpers to the steel according to T250.66 meaning that the largest required would be #3/0 Cu.

 

[jaggedben]

What happens if you don't have building steel or an a convenient crawl to run it through is that it sucks. I've had to run GECs all the way around the outside of a house in conduit (local requirement) because of situations like that. I did one run along the eaves for a hundred feet or more. Also had to do my best mole impression in an under the house crawl that was subdivided into several sections. Dumb stuff. Thank goodness this isn't a lightning prone area or I'd worry about the one with the GEC under the eaves. Not that I wouldn't blame the AHJ if it came down to it. :happysad:

 

[brian john]

You make a long run of #6 or #4 with tight bends and no need to worry about lighting, it'll find another path in lieu of the GEC you ran.