system grounding through meteal water pipe???

[Toros]

hi,why we bound metal water pipes (primary sys. grounding) as soon as they enter in to the building (within 5 ft)? How would you ground the system if there was no metal water pipe into the building?????? I am still not stuck there.... thank you

 

[infinity]

You would use one of the other electrodes listed in Article 250.

 

[Ponchik]

If new construction or you have access to the rebar then you can use it as an electrode with a minimum of 20' contact with the foundation (does not have to be continuous 20'). Otherwise a common practice is (2) ground rod with minimum earth contact of 8' each.

(NEC 2011) 250.50 has the details