I'm replacing an outlet that has 2 black wires and 2 white wires. When removing the old outlet, I didn't keep tabs on which black wire was on top and which was on bottom (as well as the whites). I'm not really sure why the order matters (if it does) but I'd like to figure out the proper way to wire this back up.
I had it wired for a while based on what I thought was the right order, but for some reason today I noticed part of the circuit suddenly stopped working; this was triggered by a light switch turning on down circuit I think. It's a motion activated light and happened to switch off just as I was testing the outlet with my voltage detector -- when I tapped the outlet is when the light went out. However, I can't reproduce this. So the outlet just before the new one worked, the new one wasn't working, and the outlets beyond it (including a GFCI outlet) were dead. The breaker nor the GFCI tripped.
I had the outlet pulled out of the wall while testing and noticed a small spark prior to the outlets down circuit going dead -- seemed like a bad idea to leave it as is, so I turned the breaker off until I can figure out the correct order.
How can I figure out which wire goes where (safely)?