I started replacing a light fixture with a fan + light, and ran into a weird issue. My contactless electrical tester indicated current despite having turned off the breaker. The light was off in the room, and outlets were all disabled, but I am kind of spooked and want to get a some advice before I touch this stuff.
Any suggestions for what might be happening? I'm afraid there might be a second circuit. It's an old 1906 house, and I just don't trust it to be wired up in a sane way.