I wired up a ceiling fan and it didn't work. I took the switch box apart to see which was the hot and which was the switch leg. When I tested from hot to neutral I got 110v and when I tested from hot to ground it tripped the breaker. I tested on a receptacle on a different circuit and got the same results. I don't understand. Can you help?

Would this happen to be a GFI or AFCI circuit breaker ? Either would have a "Test" button on the front of the CB. If so, what color button?