Need help with 220V circuit
So there's a 220V air conditioner, and it's not running. It ran last year. I tested the voltage from white-ground, and black-ground, and there's about 0.30mv coming through each.
I went into the box and tried to substitute the 30A double-breaker with another 30A double-breaker, but that gave me the same result.
I checked the ground connection, as well as continuity of the white/black, and everything was fine. Stumped, I replaced the 30A double-breaker with two individual 15A single breakers, and it's working fine.
The odds that both of these double-breakers would be defective is too miniscule to calculate, but obviously I did SOMETHING to get it to work. I need some insight into what the problem could be.
Thanks, and have a great holiday!