Greg,
I used to do a lot of work in wiring dairy sheds (parlors I believe you guys call them over there).
Cows cause a real mess if there is ANY stray voltage due to poor earthing.
The standard used to be that you had to have a maximum earth resistance of 0.05 ohms at any point to earth.
Everything was multiply bonded, it was a nightmare, I don't miss them days.
Although it did make me buy one of them Fluke multi-function testers, best (lots of) money I ever spent.
