Help with Electrical Question

I do not have a photo(deleted on accident), but here is a discription of what I came accross and I could use some help on figureing it out.

Home built in 1976 that had been rewired with new panels. There were a group of switches in the hall that did not work any more due to rewireing and remodeling. As i switched on the switch on the wall I heard a loud pop in the attic above me. I found a square D box with a blank panel cover and no breakers. It had several Romex wires in it. I took the cover off and found a horizontal bar with all the wires attached. Below the bar was a breaker looking item that would slide up and down as the hall way switch was turned on and off. Sounded just like a breaker popping. It had one white and one black wire attached. It almost looked like a contactor, but as it switched on and off, I never lost power any where.

HAs anyone ever come across anything like this?

Thanks

Sounds like an older lighting contactor. Do you know where all the romex was leading to?

Jeff

Thank you Jeff,
I looked it up and that is exactly what it was…

Charlie