Found yer problem bud

Wife was complaining that my UPS in the garage kept making a clunking sound and then the lights would flicker.

So I went down and watched, and sure enough the lights would flicker and the UPS would clunk. Looking over the voltages I would see a 20v drop and then it would come back. I happen to have a UPS on the 2nd leg of our box so I watched that one, and the voltage never shifted.

Turned off the breaker box, pulled the cover, pulled the breaker in question. boom, clearly it was a corroded contact causing higher resistance, and heat, and causing brownouts.

$8 later were back up and running, and I can sleep safer knowing at least THAT breaker is not going to start a fire.