Does anyone live in a jurisdiction where metal soil pipe (DWV) is considered part of the 'metal water piping system' and is therefore required to be bonded? Does anyone do this as a matter of course? What are the criteria to select the bonding jumper and do you connect together sections that may be separated by plastic? How about using it as a grounding electrode if it exits the house underground?
Personally I would not call what is in that pipe 'water'.
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250.52 Grounding Electrodes. (A) Electrodes Permitted for Grounding. (1) Metal Underground Water Pipe.
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250.104(B) Other Metal Piping. Where installed in or attached to a building or structure, metal piping system(s), including gas piping, that may become energized shall be bonded.....
Do you think the waste pipe may become energized?
I think that would take very unusual circumstances.
Bob Badger Construction & Maintenance Electrician Massachusetts
I suppose that bonding the drain pipe isn't a bad idea. This would even be desireable in the case of a sump pump, or a 'pump-up' toilet, or other electrical equipment being present that uses the drain line. In that case, I would prefer to make my bond at the equipment, rather than to a main line. Even cast iron pipe is assembled in a manner that may provide a poor connection between separate pieces. So let's put the electric "drain" near where the electric "leak" is likely to be!
