temporary service?

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 :)

I have an air compressor that I have not been able to use because it requires 220v and all the circuits in my breaker panel are 110v. On my electric bill in states that I have 220v service but I can not figure out how to connect it. I had four 15 amp breakers which I replaced with "two-in-one" 15 amp breakers and they work great. The clerk at the Lowe's also sold me a "double-gang" 30 amp breaker. When I put in the "double-gang" breaker I tried to measure the voltage between the breaker terminals and there was no voltage. I still get 110v between the breaker terminal and neutral. I plan on using 10-3 Romex with a seperate ground wire. I understand that I need to connect the black and red wires to the "double-gang" breaker but I am not getting a voltage reading there. What am I doing wrong? Also, the only receptacle they had that would work with my compressor's power cord only has two line connections and the ground connection. What do I do with the white wire? Any help would be appreciated.