In in-laws wanted to me to fix their outdoor light post light. It's always lit and the photocell is not working. Armed with a new photocell and some tools I tackled the project. Turned the light on. Switched a couple breakers and when the light went off, I went to work. Someone messed with the wires inside the outdoor box and bypassed the photocell. I removed the old one, installed the new one and put my hand over the cell's eye while I closed the box and the light went on.. Oops. I got lucky. Guess I never touched the hot wire. Be careful out there. No idea why the light went out with the breaker still on.