Before we purchased our house we noticed there was a bunch of romex wiring exposed in the garage. We asked the realtor to find out if it was live or not. If it was live, we wanted it closed up.
She got back to us and set it was all dead. It was put in for some small projects to install security lights outside and a light in the extended section of our garage but was never finished. No electricity flowing.
Two weeks ago one of my weekend small projects was to get a light switch to install in the side wall by our weight set and get those security lights working so we can see at night when we go out to our garbage totes. The other part was to install a small light bulb fixture above the workout section of the garage into the drywall ceiling (no studs up there).
I grabbed my trusty line tester to see if the supposed lines were really dead or not. The one from the ceiling was live if a flip was switched and dead when off. (i deduced this by seeing the wiring in the attic and from the tester). This light bulb thing should be simple (and it was). Piece of cake!
Then I headed over to the wiring in the wall near the weight set and also next to the auto sprinkler controller. The first line was dead as dead can be.
The second line sticking out, however, was not. An arc very bright in the dim garage connected the two ends of my tester, blowing out the bulb, sending smoke in the air, killing everything in that wall, and sending me flying back more scared than anything else.
"Sonofa!" I yelled. Hard to blame the realtor for being lied to, but come on. That line was brushed every time I changed weights on the weight set or reset the sprinklers' controls. That set had even been used by my squirley nephew. Any one of us could have grabbed on and gotten the shock from hell. I was pissed.
Go flip the breaker, and nothing. The entire wall is still dead. Uh oh! I hope I didn't melt any wiring inside the wall.
Back to the hardware store I go to buy a stud finder that also detects AC magnetic fields to help trace wiring inside a wall. There was power going all the way to where I wanted it, but everything was dead. Then I found a GFI that had popped hiding in the socket the sprinklers were plugged into. It was the only one in the house I didn't know about. Hit "reset" and we are ready to go.
Long story short, I installed the switch and now the security lights work great and no one died, thankfully! During the process I found out that our phone lines also have AC current running on them which explains why we have problems with our phones. The wiring in our attic is a mess. Not sure who installed it, but they have power lines running too close to the phone lines and the magnetic fields are interfering with each other. Too big of a job for me, but calling an electrician to rewire the entire house would be ridiculous. So, screwy phone lines for now.
the End.
