# Turning on a main circuit breaker



## 4Jolig (Mar 18, 2013)

Hi, im a student in high school, and i have a question about how to turn on the main breaker to a dimmer rack.

Lately in our school auditorium, the lighting system has been acting funny. The house light haven't been working, and sometimes the stage lights get stuck on when controlling them from the architectural panel. The system we have is rather old. it is a Lehigh original DX rack. There have been several brownouts in the down because of storms before these problems started happening. And the sensor dimmer racks at the larger elementary school auditorium where we do our shows needed to be reset because of the brownouts, so i figured that that's what needed to happen with the Lehigh rack. So I read the manuel, and it mentions nothing about how to reset the rack, and three was no power button on the control modegul, and no reset button. So i decided to turn of the main breaker at the bottom of the rack on and off again, figuring that's maybe how one resets it, and its meant to do that because you need to kill the power to service anyway. The breaker is located at the bottom of the rack, and it is about 2 inches wide. So i went to turn it off and it had some resistance but then it turned off with a little effort. When i went to turn the rack back on, the breaker switch came up, but it would not click on. I pulled it up with a good amount of force too, and it still wont click. What is wrong with it? Do I have to pull up harder on it? Is it not meant to turn back on? Was the system just old and the breaker no good anymore?

Also, i know i probably shouldn't have touched it in the first place, and that i am still learning and unexperienced and could have gotten severely injured dealign with the high voltage and current. so please help me buy simply answering my questions. (also please excuse any spelling...I'm not the best...)

-Thanks


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## Call911 (Mar 18, 2013)

Don't touch it. Don't look at it. Don't go near it. Get your teacher to talk to buildings and grounds ASAP. You have no reason being anywhere near the dimmer rack as a student. This is high voltage and can easily harm or kill you.


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## JD (Mar 18, 2013)

Breaker may be bad. Actually, your logic wasn't, you were on the right track. But, as a student, you really should not have gotten involved in the fix. 
Sometimes the springs age a bit and if a large breaker hasn't been operated in many years it may be quarrelsome to reset.


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## Robert (Mar 19, 2013)

This is my opinion. 
You didn't break it. A breaker should tolerate being turned off and reset. If the breaker is bad, you may have helped yourself and saved someone else down the road. Having talked to several people about the danger of turning off a modern breaker, the consensus was there is no danger or concerns with operating a breaker. In fact, some suggest operating a breaker once in a while to verify it's operation. Let someone you know, that you trust, what you did and why. It makes sense. To my knowledge and understanding (and that of my friends) OSHA and NFPA do not have any code requirements about turning off a breaker. Arc flash is not a concern in operating a breaker. Breakers have arc flash tubes that direct the flash inside the panel. A lot of equipment requires a hard boot (perhaps a breaker reset) to clear voltage irregularities. Its what I would have done.
A breaker not resetting may indicate a problem with the breaker or something else down the line. You should get somebdy else to look at it now.


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## LavaASU (Mar 19, 2013)

Ok. I'm going to be in the minority here and say I don't see anything wrong with a high school student working with dimmer racks if PROPERLY TRAINED AND SUPERVISED.

However, you need to get a competent adult involved to check that breaker. And train/supervise you if you will be working with the dimmers. I will say typically it's best to turn off main breakers when under no or a small load unless in an emergency. However they should certainly be able to withstand repeatedly being switched at full rated load.

Without seeing it I'm not sure whats wrong. It could possibly be a multi-step reset, or bad, or could just need to be pushed harder, or... someone with more experience than you needs to figure that out.

Oh, and a hard reset (breaker flipping) is what I would've done if that makes you feel better. So at worst you uncovered a failing component.


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## Les (Mar 19, 2013)

I also agree that students being in the dimmer room isn't inherently a bad thing, but there should always be an authorized and competent instructor/adult present any time modules are being removed - while observing LOTO procedures, of course.

This is coming from someone who hot-swapped and cleaned Sensor dimmer racks by himself in high school... Boy did I have a lot to learn and oh my, was I lucky. Ill informed, but lucky.


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## FMEng (Mar 19, 2013)

Robert said:


> This is my opinion.
> Having talked to several people about the danger of turning off a modern breaker, the consensus was there is no danger or concerns with operating a breaker. In fact, some suggest operating a breaker once in a while to verify it's operation. Let someone you know, that you trust, what you did and why. It makes sense. To my knowledge and understanding (and that of my friends) OSHA and NFPA do not have any code requirements about turning off a breaker. Arc flash is not a concern in operating a breaker. Breakers have arc flash tubes that direct the flash inside the panel. A lot of equipment requires a hard boot (perhaps a breaker reset) to clear voltage irregularities. Its what I would have done.
> A breaker not resetting may indicate a problem with the breaker or something else down the line. You should get somebdy else to look at it now.



In my opinion, circuit breakers should be given some respect. Arc chutes are there for the normal arc of the contacts as they open or close under load. The chutes are not there as any kind of protection for arc flash. The explosive force of an arc flash can rupture through the case of the breaker. Thankfully, internal breaker failures causing an arc flash is very rare, but it can happen.

One of the smartest electricians I know takes the simple precaution of standing aside at arm's length when operating a breaker. Should the thing explode, his face and body is not directly in front of the it. Leather gloves and a sleeves with non-synthetic fabric are a good idea, too.

http://www.circuitbreakersblog.com/...inghouse-pc32000-molded-case-circuit-breaker/


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## tjrobb (Mar 19, 2013)

IIRC, there is a minimum level of PPE required to operate breakers, but for the life of me I can't remember what. My guess would be face shield and hearing protection. That being said, it would really apply only to turning them on and then mainly to higher-power breakers. I'd have to check NFPA 70E to know for sure. (Note that the info herein is out of memory, call a pro if in doubt).
.


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## JD (Mar 19, 2013)

Yes, breakers can catastrophically fail, but it is rare, and in 40 years I can't recall one in the 200 to 400 amp class failing catastrophically for anyone I know. Also, in this case, the breaker is on the rack, so there is a second breaker upstream in the mains distribution. 

Still, I agree that at this point it is better to place the problem in someone else's hands. As said above, resetting was the next logical step. 

To whomever ends up fixing it, I would impart the following; Had the same problem myself in an old theater back in the 1970's. Turned off the mains, tied in, and then went to turn it back on and it was a no-go. I could feel the spring tension pushing back but it would never make it to the "click." Increasing the velocity of the turn-on did the trick after about 4 tries. In this case, why risk it? They should find the upstream breaker, turn that off (lock and tag), then get nasty on the rack breaker. 

The best procedure (if you do not have a show coming up) would be to have maintenance bring in a contractor to replace the breaker so that the next time the rack needs to be shut down, it can actually be turned back on. After all, a breaker that does not turn on is a defective breaker.


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## Robert (Mar 20, 2013)

You know, I have to agree with safety glasses and a non-melting shirt, but I doubt that an electician will do this for a standard 15 amp breaker. This will lead me to ask a new question on this thread. What amperage breaker deserves precautions as mentioned earlier.


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## 4Jolig (Mar 20, 2013)

Thanks to everyone

I ended up just getting help, and it turns out that i just wasn't pulling hard enough. However it ended up not fixing the problem. We were going to have the local theater service company come in and do a diagnostic and get deep into the problem, but that got snowed out and now their still rescheduling it. Also, i do have a pretty good idea of what i am doing, even though i do have a long long long way to go. No one really knows, or even ever heard of Lehigh. i do know the most about the system their, and i barley know anything about it. But again thanks to all the people that helped.


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## Robert (Mar 20, 2013)

So for those who say turn away, dopn't touch, too dangerous, forbidden, blah, blah, blah. What amperage breaker do you consider too high to have somebody touch? Can you re-set a dimmer at 10, 15, 20 amps? What about a main breaker at 40 amps? Maybe 50 amps? Are breakers so poorly designed that they are inherently danergous? Maybe 800 amps under full load? Safe as long as they are in a panel? What are your concerns? If a peice of equipment is too sensitive to power fluctuations from a breaker, how could it get a UL listing? Yes stupid things can be done to anything. Let's talk about normal operations.


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## Robert (Mar 20, 2013)

Sounds good. Just remember, safety is the main concern and is the reason most will shy away from giving any advice to you. Most commercial electricans could look at a breaker and replace it and not every theatrical supply house has an electician on staff. They may be certified to do service work, but may still call an electrician to do power work. Other issues will likely need somebody familiar with dimming systems to solve, so they may be a good choice to call.


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## Les (Mar 20, 2013)

4Jolig said:


> Thanks to everyone
> 
> I ended up just getting help, and it turns out that i just wasn't pulling hard enough. However it ended up not fixing the problem. We were going to have the local theater service company come in and do a diagnostic and get deep into the problem, but that got snowed out and now their still rescheduling it. Also, i do have a pretty good idea of what i am doing, even though i do have a long long long way to go. No one really knows, or even ever heard of Lehigh. i do know the most about the system their, and i barley know anything about it. But again thanks to all the people that helped.



You could try calling Lehigh and see what they say. "Straight from the horse's mouth" is usually the best place to start.
Lehigh Main: Welcome to Lehigh Lighting - Controls, Dimming, Fixtures
Useful-looking phone numbers: Lehigh - Support

We also have a member who, last we heard, was an employee of Lehigh. You can try sending him a PM.

Damian Delaney aka Naimad
ddelaney[at]lehighdim.com


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## JD (Mar 20, 2013)

Robert said:


> So for those who say turn away, dopn't touch, too dangerous, forbidden, blah, blah, blah. What amperage breaker do you consider too high to have somebody touch? Can you re-set a dimmer at 10, 15, 20 amps? What about a main breaker at 40 amps? Maybe 50 amps? Are breakers so poorly designed that they are inherently danergous? Maybe 800 amps under full load? Safe as long as they are in a panel? What are your concerns? If a peice of equipment is too sensitive to power fluctuations from a breaker, how could it get a UL listing? Yes stupid things can be done to anything. Let's talk about normal operations.



My own feelings (and that's what they are, "feelings", no science involved) is that I have never been too worried about enclosed breakers at or under 400 amps. Pretty common product, with a lot of history. Of course, I have never had to engage or disengage under full load. Would avoid that, although lets face it, you never truly know about loading when it's in a cabinet. When you start getting into the big stuff (1200 amps, or a 480 transformer feed) protection is a must. I am sure someone will come by and spec out at what level protection on an enclosed breaker becomes necessary, but I agree that I can't remember anyone ever getting dressed up to reset a 20.


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## Esoteric (Mar 21, 2013)

FMEng said:


> In my opinion, circuit breakers should be given some respect. Arc chutes are there for the normal arc of the contacts as they open or close under load. The chutes are not there as any kind of protection for arc flash. The explosive force of an arc flash can rupture through the case of the breaker. Thankfully, internal breaker failures causing an arc flash is very rare, but it can happen.
> 
> One of the smartest electricians I know takes the simple precaution of standing aside at arm's length when operating a breaker. Should the thing explode, his face and body is not directly in front of the it. Leather gloves and a sleeves with non-synthetic fabric are a good idea, too.
> 
> Arc Blast Damaged Westinghouse PC32000 Circuit Breaker | Circuit Breakers Blog - Expert Safety and Usage Information



Funny enough (or not), my electrician while on his day job last week flipped a 400A breaker and got an arc that actually blinded him for about 5 minutes (after throwing him well clear of the panel). He wet himself. He thought he had died.

Mike


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## FMEng (Mar 21, 2013)

The circumstances can play a role in how much caution to exercise, too. Let's say a 200 amp, three-phase breaker suddenly trips and the load on it is known to be comfortably less than the rating. More caution should be taken, because there is good reason to suspect a circuit fault downstream of the breaker. Closing a breaker into a dead short is when bad things can happen. A wise electrician would do some investigating to determine WHY it tripped in the first place, before attempting to reset it.


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## LavaASU (Mar 21, 2013)

Esoteric said:


> Funny enough (or not), my electrician while on his day job last week flipped a 400A breaker and got an arc that actually blinded him for about 5 minutes (after throwing him well clear of the panel). He wet himself. He thought he had died.
> 
> Mike



Yikes. What voltage was that breaker?


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## JD (Mar 21, 2013)

FMEng said:


> The circumstances can play a role in how much caution to exercise, too. Let's say a 200 amp, three-phase breaker suddenly trips and the load on it is known to be comfortably less than the rating. More caution should be taken, because there is good reason to suspect a circuit fault downstream of the breaker. Closing a breaker into a dead short is when bad things can happen. A wise electrician would do some investigating to determine WHY it tripped in the first place, before attempting to reset it.



Investigating any unknown trips is good practice, even if it's only a 20 amp breaker. When the cause is known, we all know enough to rectify the situation first. When the cause is unknown, that is a big trouble flag! If a 200 or 400 amp breaker trips, the worst thing you could do is simply flip it back on. You may endanger someone downstream. For example, what if a section of staging cut through a feeder? 

For whatever reason, I have never had to _*reset*_ a breaker of that size in all my years. Just random good luck for once. Still, if I had seen one tripped, my first reaction would have probably been there standing with my mouth open, knowing something pretty bad had just happened somewhere. I would want to find out what happened before I made my second move.


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## mstaylor (Mar 21, 2013)

I was just out of HS and working in the theatre over night. A problem in a transformer outside kickers800 amp breaker inside. It killed our whole wing. I kicked it back on twice before the power company came. Not my smartest move but I lived.

Sent from my C771 using Tapatalk 2


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## Robert (Mar 21, 2013)

So just looking online for a little research information on breeaker issues. Found a site with some intersting information. Confirms what FMEng says about shirts and safety glasses for less than 240 volt service. Same site he used.

Arc Flash Hazards - 1976 to Today


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## ruinexplorer (Mar 22, 2013)

A little frightened at the "knowledge" being expressed here and some of the very fortunate non-issues that have been shared. Yes, the NFPA 70E does have specification on what PPE is required for various levels of operation of a circuit breaker. There are five categories of PPE. I do not have the 2012 charts to share (here's the 2012 PPE, just not in a chart form), but here are the requirements from 2009. 

ELECTRICAL SAFETY COMPLIANCE CHART
FOR NFPA 70E AND CSA Z462

Please note that in the safety compliance chart, this is just a guide which may or may not reflect the PPE requirements for your specific space. The only way to know that is through a risk assessment study by a licensed electrical engineer. The biggest risk in our industry is that most of us have been trained to think we are successful despite repeated near misses. Just because we don't know that we are working with something dangerous does not mean that it isn't. Just because we will call the person who is the lead electrician on a show a Master Electrician, this does not mean that the person is actually qualified to have that title. Yes, there is arc-flash risk whenever you flip a breaker or switch. Yes, the older a switch is, the more likely it will fail. There is also discussion on how often a circuit breaker should be tested. If it is not designed to be a switch, then it has a rated limit on the number of times it is designed to be switched off and on. Here's a good primer on the 70E requirements. Your facility manager really should have the updated copy.


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## Esoteric (Mar 22, 2013)

LavaASU said:


> Yikes. What voltage was that breaker?



480 Volts


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