Farm

[Oakey]

I have been rewiring an old farmhouse for over a year. A slow job to say the least but now its time to do the main service. Underground is done and I am 99% ready to go. Today I went to do the switch over and ran into a grounding question that I hope I can get some advice for.
The house has a remote well about 150ft from the house with a small shed above it where the sub panel and controls are. When I first started the project there was a metal well line out to the pump and the grounding clamp was inside as it first came above the grade in the house. In that time it has been replaced with a plastic well line but the old metal line was left in the ground just cut off from the well head and its still stubbed up in the house with the old clamp on it.
My question is...is this an acceptable choice for my grounding as well as my 2 ground rods?

 

[roger]

Oakey, there is nothing wrong with using it, so seeing how it is there, I would connect to it.

It could be argued that it must be used looking at 250.52(A)(7)

(7) Other Local Metal Underground Systems or Structures Other local metal underground systems or structures such as piping systems, underground tanks, and underground metal well casings that are not effectively bonded to a metal water pipe.

It may not truly be a system any longer but it is underground piping.

Roger

 

[tom baker]

If you only have a single/multiwire branch circuit to the well building then you don't need a grounding electrode system, see 250.32(A)
However if its supplied by a feeder then a grounding electrode system is required, per 250.32 and note that you should not reground the neutral at the well building.

 

[Oakey]

Thank you for your replies..Roger the piping to the old well seems like the way to go so I appreciate it. Where I live there are very few houses with wells anymore and my experience with this is limited.

Tom this wire run started out as a sole feeder but since has been converted to a sub panel for extra goodies like lights etc. The price I pay for pulling extra large feeder wires . I have read article 250.32.... so 2 ground rods would do or can I use the well ground for the electrode system?

 

[hornetd]

If that well casing is metal I'd be very tempted to bond the old water piping to it so that it would become part of the grounding electrode system. I doubt you could get a better ground then a deep well with a metal casing in the absence of a large underground metallic water system.