"mm" wrote
We have a bedroom in attic that we seldom use. But with holiday
houseguests
it is getting use. But, the electric baseboard heater is not working.

BTW, has it ever worked? How long have you lived there?

Good Question! and the answer is YES it has always worked in the past, but
we had not checked it this winter until now.

This should answer most of the suggestions (I appreciate them!) - We have
lived here for 30+ years - The panel has not been modified during that time
nor the bedroom's wiring.

I understand how the voltages would be as measured if somehow both hots were
being fed from same phase - But at a loss to know how this could be.

We did have some bathroom rewiring done this past summer, but it should not
affect this area. But you never know!

Graham