In my shop (ex - garage) I have two 120V circuits fed from our house main 400A panel. One is 15A and powers the lights (3.5 amps) and garage door opener (1 amp). The other 120V circuit (20A) feeds all the wall outlets, and only a radio was on. I think this is pretty traditional house construction setup. I also have a small sub-panel in the shop that uses a 50A breaker from the main, and creates three 20A 240V circuits, for tools (inc dust collector and bandsaw).
This afternoon, as I've done many times, I had all the overhead lights on, as well as the dust collector. I turned on the bandsaw (which I'd been using fairly heavily), and the lights went out, breaker blown. The bandsaw and dust collector were still running, as was the radio on the 120V 20A circuit.
My basic understanding of how this stuff works is, that's not supposed to happen. But the lights went out absolutely the instant I turned on the bandsaw.
Any input as to what happened would be welcome! I just flipped the breaker back on and continued on my way, but didn't actually need to use the bandsaw anymore. I did use the jointer which probably sucks about the same amps.