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The Mystery Circuit...

Discussion in 'Safety' started by RedmonwantsEOS, Jun 16, 2008.

  1. RedmonwantsEOS

    RedmonwantsEOS Member

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    This happened a few days ago, and got solved today. Good way to spend a day at school.
    Ok, last week, we had many severe storms here in Northerna VA, with balckouts and power surges. Well, my friend Phil and I were hired to run lights for a ballet recital over the weekend. At the first rehersal, we had no power to two out of the three duplex outlets in our control booth. We needed them both for our sound and lighting console. Ok, I thought, it must be a dead breaker. All of the other outlets in the Auditorium are good. I check the panel. Nope, all on. So, I informed our building engineer Friday morning. He looked at it in the afternoon, but couldn't finid anything wrong. No big deal, we have one outlet, we can get by using an extension cord for the ballet. It worked out, but we still had two dead outlets.
    Today, Monday morning, my favorite electrician, Scott and one of his assistants arrive to figure out what is going on. I had my study hall "exam" for the first two hours of school, so I got to observe and help the entire time. First thing we do is check EVERY circuit breaker panel in the school. Only one tripped breaker, and its for the kitchen. So, Scott decideds get out his Amprobe CT-100 circuit tracer to find out which breaker these outlets are on. He plugs it in, and he starts to trace the wire. No signal on the panel which the outlet is labeled for. So we start checking other panels, nothing. We do get a faint signal in the ceiling however. Well, why is the third outlet working asks Scott? So, we decide to trace where that outlet goes. It goes to the 120 volt panel serving the Auditorium. But, the circuit it is on is labeled "COMP. (Computer) REC. 502 503 504" Well, thinks Scott, there are two outlets in the hallway, what are they hooked up to? We test them. One is another labeled the same as above, another one is labeled "(Crossed Out->) UNKNOWN. 2 Exhaust Fans Bathrooms" Wow, we need to get all the panels in this school re-labeled I think to myself. By now, Scott, the building engineer, the other electrician, and myself, are stumped. The only thing we can think of is that some wire got burned in the ceiling somewhere. Well, Scott and our engineer take a look at the original blueprints for the school, and discover that the outlets are actually connected to our dimmer rack! Some idiot had gone in and turned off the breaker for the one "constant" module in our dimmer rack, causing the outlets to go out! We we got that figured out at the end of the day, all I could do was laugh, after all the work we had done. Turns out that there were originally some spotlights controlled in the "projection booth" through our original lighting system, replaced in 2006. They decided that it would just be easiest to leave the outlets on the dimmer circut, instead of pulling new wire. Wow.
     
  2. Wolf

    Wolf Active Member

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    Location:
    Cincinnati, Ohio
    Sounds like a long day. Well at least you know something new. And yes it does sound like you need to re-mark all the circuit brakers in the school lol. Well know you could turn off the dimmers and ask some noobby to check it and see what he/she does (but that would be a little mean i guess).
     
  3. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Location:
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    Get out the P-Touch Label Maker NOW, and label both the outlets AND the Constant Module. What if someone decided to use that constant module in another dimmer slot to power an ML or gadget? Then the LightBoard would have to send DMX to the dimmer rack to power itself--the ultimate Catch-22! (Don't try this at home, kids.)
     
  4. RedmonwantsEOS

    RedmonwantsEOS Member

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    Oh, they are ALL marked now, clearly marked.
    I really do not think that anybody would swap the modules out. I didn't even know that they could just be pulled out until yesterday. And the constant module is a LOT lighter than a regular dimming module.
     

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