Total posts : 45366
by MRAM 1500 kHz
I ran into a situation at my father-in-laws house along these lines.
His water heater needed replaced. When I disconnected the supply lines from the tank, arc-spark. Seems that the neutral connection at the house service entrance was bad. That being the case, the majority of the load current for his house was finding a path to ground through his water lines and the connection at the water tank was a big part of that connection.
Had I been hanging onto both pipes when they disconnected I’d have received a pretty hefty shock.
We put a jumper between the supply lines so that next time there’d be no surprises. The electric supplier was called to repair the neutral.