Miswired a switch, entire building power went down


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Old 11-21-14, 05:07 PM
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Miswired a switch, entire building power went down

Apparently I don't know as much about simple wiring as I thought I did. I was installing a new timer switch for our buildings outdoor lighting. Hit the breaker to turn it on to test, and BAM! The timer switch practically exploded and all of my power shut down. I checked the breakers, they are all on.

Is there anything I can do to fix this now, or do I need to make an emergency call to an electrician tomorrow? I'm an idiot.
 
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Old 11-21-14, 05:26 PM
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Unlikely all the breakers are still closed. Is there a main breaker outside? Sometimes, a larger breaker upstream will trip before a smaller breaker on the branch circuit.
 
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Old 11-21-14, 05:38 PM
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Remove the switch. Hopefully it only controls the lights and there are no other critical connections inside that particular box.
Cap off all wires inside box with wire nuts.
After wires are safely capped off, attempt to restore power and post back results.
Turn each and every breaker to the off position, and then back on.
 
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Old 11-21-14, 06:09 PM
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I removed the switch, and capped the wires. I then switched all the breakers off then on in all of the boxes (there are 4 in the building). Nothing. I then went outside and also reset our two main units. On one of them, the handle refused to remain in the on position after reset.

I finally got the handle to stick, though it was still wanted to come down, went back inside and reset the culprit breakers again. Nothing. Five minutes later, everything suddenly came back on. Not sure what the delay was about. I went back outside and the loose handle was now rock solid. I'm glad everything is working now, but I'm still a bit concerned that I did some damage somewhere.

Anyway, thank you all for the help. I need to educate myself more before I touch another wire.
 
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Old 11-21-14, 06:31 PM
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It's late there. Check back tomorrow and hopefully one of the electricians can give you some input on what may have happened. Sounds like you're in an industrial building.
 
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Old 11-21-14, 06:41 PM
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then went outside and also reset our two main units. On one of them, the handle refused to remain in the on position after reset.
Is this the main switchgear? Are there two main breakers or are these fusible switches?

Five minutes later, everything suddenly came back on. Not sure what the delay was about. I went back outside and the loose handle was now rock solid.
I suspect you have an issue with one switch and this may have been the best way to find out about it before a complete failure. I think if you have a reliable contractor who normally does your service work that you should have him look at this for you.
 
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Old 11-21-14, 07:19 PM
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Here are the outdoor boxes I was referring to.

The right one is the one I was having trouble switching back on. However, the one on the left is the one that is part of the circuit I blew.

Parts of our system are very old. Several of our boxes, including the one I was working with, are Federal Pacific.

Here is the switch I was working with. I had blue in L1 and orange in NO. That wasn't working, so I switched orange to NC.....that's when everything went bad. You can also see where it blew up, right on that black object in the middle of the picture.

I obviously have no business working with circuits. I assumed this switch was as foolproof as a standard light switch.
 
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Old 11-21-14, 07:38 PM
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Those are both switches, not circuit breakers, they do not trip like a circuit breaker. I am assuming because of their location they are both fusible switches, did you replace any fuses? The right switch looks like it might be a 200 amp switch, but the left one is smaller and probably a 100 amp switch. I am also judging from the conduit sizes below the switches.

My advice is to get a good electrical contractor to come take a look. It is a mystery to me how you could have lost power and then have it magically return. Like I said, switches do not trip. If the fuses had blown the handles would still have been in the up "ON" position.
 
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Old 11-21-14, 10:30 PM
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I think you may have created a short with the way you have it wired.
Is this your timer? Check out the diagram.
http://www.intermatic.com/~/media/In...ries_2pgs.ashx
 
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Old 11-22-14, 05:31 AM
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I agree with Joe, you likely have some blown fuses. Pull them out and check with a meter.

Sounds like your issue was a phase to phase short.
 
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Old 11-22-14, 06:12 AM
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Thanks fellas. I'm going to have an electrician come and install my switch, as soon as a non-exploded replacement is obtained. While he's here I'll have him check the fuses on the switch boxes.
 
 

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