ollie989898
Member
It's definitely bad practice, not sure exactly why it's frowned upon
I know cattle are very very sensitive to even small electrical current hence why parlours and the like are so carefully earthed. I would have thought using a building as an Earth is bad because although the frame is metal, its all sank into concrete/floor and so won't be particularly useful as an earth.
I've seen someone use a scaffold pole as an Earth, driven in deep by a telehandler. Pouring a bucket of water in and around it helps ensure conductivity.