D Yuniskis wrote:
Sylvia Else wrote:

Grounding the mains to "plumbing" *was* common in the US many
years ago. Now, I believe, you *must* ground to a metal
rod driven into the earth (8 ft?). Note that if the water
meter was removed, your earth-through-plumbing would fail.


This is how GFCI breakers work -- they watch for current "leaking"
off to ground someplace other than in the "return" conductor.

In this case the GFCI (or RCD in AU) will not trip as the current through the
load is the same going in and out. I have RCDs on all 3 phases and none of them
tripped.

Tony