I'm working in a building with a 240V 3Ø service for 'power', and a 120/240V 1Ø service for 'lighting'.
There are welding plugs (240V 1Ø) run off the 'lighting' service. The strange part is I get ~130V from one leg to ground, and ~140V from the other leg to ground.
I speculating the POCO is using a delta 4-wire arrangement to supply the two services.
Is my voltage-to-ground reading indicative that the welding plug is not properly bonded? (i.e. measuring delta-system capacitive 'ground' instead?)
I ran out of time on this visit... I'm going to delve into it further next time.
