In alot of old houses I see old non-grounded systems with grounded receptacles installed, and a green #12 thhn running to the nearest water pipe. Is this or was this ever an acceptable practice? I cant seem to find it in the book. Any help would be appreciated.
Well this has been descussed. and some feel that it is not allowed but I ask then what would of been the perpose of the allownce for406.3 (C) or (D)(1) which refers you to 250.130(C):
(C) Nongrounding Receptacle Replacement or Branch Circuit Extensions. The equipment grounding conductor of a grounding-type receptacle or a branch-circuit extension shall be permitted to be connected to any of the following: (1) Any accessible point on the grounding electrode system as described in 250.50 (3) The equipment grounding terminal bar within the enclosure where the branch circuit for the receptacle or branch circuit originates
(4) For grounded systems, the grounded service conductor within the service equipment enclosure
(5) For ungrounded systems, the grounding terminal bar within the service equipment enclosure.
the code has said this since 93 as far as I can tell but with the 2002 saying that the water pipe farther than 5' from where it enters the building cannot be called as the grounding electrode.
So my there is my delima why did the nec include this allownce?
If you can get to this part of the pipe then you could either get to the panel or the GEC. but I will leave this one alone.
It was once allowed. It is not now allowed. I believe with the proliferation of plastic water piping you can no longer be assured of continuous copper piping throughout the house. You must run an egc back to the electrode, or the panel. The piping in the house is not part of the grounding electrode system.