There seems to be some sort of phenomenon associated with arc-welders that escapes me.

This week , for the second time this year, i was called to a welder's shop that apparently caused a transformer fire. By this i mean the transformer on the utility pole.

The first time , i dismmissed this as a faulty t-former. This time i'm not so sure.

Both times, the service was small, 100 amp 120/240 residential, both times the welder was a rather large 50A unit. Both times, there appeared to be no other damage to panels, breakers, etc. Nothing tripped either...

I realize i lack any solid numbers here. Has anyone else dealt with this sort of scenario?

Sparky
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