Grounding Question

[Richterfan]

I have 7 unit condo structure, the building is all wood ,no steel, all the plumbing is all plastic , except for the 5 ' ductile iron water pipe, stub in the building

I have a full size ground to 20' of incase concrete rebar,I have a full size to 3 Caldweld rod*

Question does the ductile iron need a full size ground?*

 

[eprice]

I have 7 unit condo structure, the building is all wood ,no steel, all the plumbing is all plastic , except for the 5 ' ductile iron water pipe, stub in the building

I have a full size ground to 20' of incase concrete rebar,I have a full size to 3 Caldweld rod*

Question does the ductile iron need a full size ground?*

I think you're saying that the ductile iron water pipe extends 5' into the building. Is there at least 10' of ductile iron water pipe underground outside of the building? If so, then yes, 250.50 requires you to use it as a grounding electrode. The grounding electrode conductor to it will need to be sized according to Table 250.66.

 

[kwired]

If you have 10' or more of metal water piping buried in the ground it is a grounding electrode and is required to have a grounding electrode conductor run to it.

If all you have is 5' of metal piping inside (plus less than 10 feet outside) you do not have a recognized grounding electrode. You also don't have a metallic piping system and do not need to run any grounding wire to this pipe. It is just an isolated section of metal piping - unless there is something there that could be a source of energizing it - but then the EGC of whatever that may be is acceptable to bond it to.