Electrical switch dilemna

Ok, I am not sure of all the details, but I have a friend who was replacing an existing light fixture in her bathroom with a new. She did not turn off the circuit breaker, and when she wired the new fixture on, there were sparks and it killed the power on that circuit. She reset the breaker, and now everything works fine. I went over there today, and I was going to replace the wall switch with a new one, cause I figured that would solve hre new problem. I tested the wiring with a volt meter to make sure the wiriring was still good, and the wires leading to the switch were hot. I also tested the wires at the outlet to the fixture, and they were hot as well. My dilemna is, I do not think this is normal. Should the light fixture be active, if there is no switch connected? I think I am confusing myself here and overanalyzing the problem, but how can the switch turn the light on and off, if the light is on without any switch there? Any help would be appreciated, thank you in advance

 

it sounds like someone wired the fixture with a switched neutral. The hot line goes to the fixture first, through the bulb, then through the switch and back to the fixture to pick up the neutral wire from the breaker panel. In this configuration (against current NEC, and dangerous as you have found out) both sides of the fixture will be live up to the switch. To check for this condition, find the feed from the breaker panel and see if the hot is landed on one side of the fixture and the feed to the switch on the other. the white fromt the switch will be tied to the neutral from the breaker panel. Basically swap the hot and neutral connections from the breaker panel to fix this problem (be sure to observe the correct wireing color codes...black-hot, white-neutral, green-ground)