So in the electrical trade there are a lot of laws and rules that need to be followed. Topping that list are the three that I have lived by since I was 14.

1. Don't trust anyone that says "yeah it’s off"
2. Even after you are sure it’s off, treat every wire as if it’s still hot.
3. Assume that there could be more than one source of power in any
given box

Well last week I was working on replacing the shop light switches with some occupancy sensor wall switches. This saves money in not only electricity, but lamp life as well as overall ballast life.

Anyway, all the lighting up here at work is 277v, not like the standard 120v we all have at home. So I busted out the blueprints, tracked down the circuit for that switch, shut it off. Then I proceeded to take the wires out. I also got rid of the other three way switch over by the roll up door, I have never used it and it would have needed another $75.00 sensor switch, so I just took it out.

Before testing I poked my tester inside the box and received no indication that there was anything left in there that was hot. I even tested the tester on an extension cord, to make sure I was using a good tester.

Following rule # 2 I used my insulated needle nose pliers to start pulling wires out of the box. That’s when evidently there was indeed more than one source of power, fortunately I was not touching anything metal, and all it did was to arc across the pliers to the box. After discovering what happened, I went looking for the breaker that I tripped so I could mark it. Well it happened to be a main in another sub panel a 125amp breaker. That’s when I decided to wait till everyone went home and I would throw the main 800 Amp and the emergency circuits off, I was not taking another chance like that.


Box




Switch


Pliers




And finally finished. Still waiting on the special blank out cover.


Now all that being said, these switches are really a great product. There are all kinds of settings and adjustments on them. If I walk in the shop, even before the door is 1/4 of the way open the lights come on, and if I'm out in less than 2 and a half minutes they shut off in that time. If I stay past that time, then they go into the specified time set.

Anyway, In 15 years up here, that the first time I have ever tripped a breaker from all the electrical work I have done here.

And I just realized something.....its sad that the first report of the year I post and it has nothing to do with motorcycles....

 

Wow, good save Deej! But I have a question! That appears to be #12 wiring in the box. So was one of those circuits connected to 125Amp main breaker? Or did it get past the breaker on that particular circuit, and esculate to the main. There is no way that #12 wire should be fed from a 125 amp main. Was the testor you used a proximity testor? That is scary that it didn't indicate power present! But, it looks like the rules saved our humble moderator and that is all that counts!

Just wondering!

 

Yes a #12 can be if it from a transformer that is pushing 480V

 

And yes my tester is a proximity tester. It's this model.

 

Remember the higher the voltage the smaller the wire.

 

i have done that before.....lol