# MCC Question



## KevinKM (Oct 8, 2012)

Later this evening an operator complained of smoke coming from a MCC Panel. It seems that when he turned the main breaker on, it was shortly after that he noticed a smoke smell. He then opened the panel and observed smoke. I have not had a chance to investigate yet, will do that tomorrow. Just wanted to get some ideas on where to look. He did not push the start button for the pump to engage. This is a Cutler Hammer motor starter, soft start. It does contain a control transformer and industrial relay for the control circuit. Any help would be appreciated. Thanks in advance.


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## glen1971 (Oct 10, 2012)

Printed circuit board on the soft start? Wires?? I've had an MCC that had a soft start fed with wire, and not bus bars, have a loose connection in the back of the gear where they terminated to the bus bars fail and start melting the insulation..


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## JRaef (Mar 23, 2009)

KevinKM said:


> Later this evening an operator complained of smoke coming from a MCC Panel. It seems that when he turned the main breaker on, it was shortly after that he noticed a smoke smell. He then opened the panel and observed smoke. I have not had a chance to investigate yet, will do that tomorrow. Just wanted to get some ideas on where to look. He did not push the start button for the pump to engage. This is a Cutler Hammer motor starter, soft start. It does contain a control transformer and industrial relay for the control circuit. Any help would be appreciated. Thanks in advance.


Can't smell it from here, but generally, smoke = bad no matter what it is. :whistling2:

There are a lot of things that are supposed to prevent smoke from being released from electrical equipment, so something has failed to perform its essential duty there. If it's a relatively recent MCC with an IT Series Soft Starter in it, they required a 24VDC power supply. If you are lucky, maybe it's just that the little power supply fried itself and didn't take out the Soft Starter PCB in the process. 

If it's an old one, like the CH/Westinghouse Easy Starts, they had cooling fans that ran all the time when power was available. Another lucky thing to hope for is that one of the fans seized up and fried. Those are easy to replace.


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## sparky970 (Mar 19, 2008)

KevinKM said:


> Later this evening an operator complained of smoke coming from a MCC Panel. It seems that when he turned the main breaker on, it was shortly after that he noticed a smoke smell. He then opened the panel and observed smoke. I have not had a chance to investigate yet, will do that tomorrow. Just wanted to get some ideas on where to look. He did not push the start button for the pump to engage. This is a Cutler Hammer motor starter, soft start. It does contain a control transformer and industrial relay for the control circuit. Any help would be appreciated. Thanks in advance.


I'm guessing it will be obvious once you take a look


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## gesparky221 (Nov 30, 2007)

Why would an operator be opening a panel to see what let the smoke out? Ever hear of NFPA 70E?


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## KevinKM (Oct 8, 2012)

Yes, They are qualified.


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## vileislepore (Jan 25, 2013)

KevinKM said:


> Yes, They are qualified.


Who says they are qualified? Do they have actual electrical training? In my facility, no one is qualified to even walk into a room w/ electrical equipment unless they have electrical training or are escorted by someone that is. No operators are qualified.


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## KevinKM (Oct 8, 2012)

NFPA 70e says they are qualified. When it comes to safety training our company take the approach of no one left behind. We all take the same safety training not just some take LO/TO, some fall arrest, some confined space, and some NFPA 70e. As far as classes I hae four years worth of schooling and attend eight to ten weeks a year of classes, and their is lots I am not able to work on. It is good to know your limitations.


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## EBFD6 (Aug 17, 2008)

KevinKM said:


> NFPA 70e says they are qualified. When it comes to safety training our company take the approach of no one left behind. We all take the same safety training not just some take LO/TO, some fall arrest, some confined space, and some NFPA 70e. As far as classes I hae four years worth of schooling and attend eight to ten weeks a year of classes, and their is lots I am not able to work on. It is good to know your limitations.


Your OP was over a month ago........what did you find?


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## hardworkingstiff (Jan 22, 2007)

KevinKM said:


> It seems that when he turned the main breaker on, it was shortly after that he noticed a smoke smell. ....Thanks in advance.


Snake across phases on the load side of the breaker? :jester:

Let us know what it really is please.


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## JRaef (Mar 23, 2009)

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hardworkingstiff said:


> Snake across phases on the load side of the breaker? :jester:
> 
> Let us know what it really is please.


Yeah, that'll do it.

Not mine, but a great example, off of Contractor Talk.


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## vileislepore (Jan 25, 2013)

JRaef said:


> Yeah, that'll do it.
> 
> Not mine, but a great example, off of Contractor Talk.


Nice! I once had a mouse short the line side of a 2500A main breaker. Ill never forget that smell!


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## eric7379 (Jan 5, 2010)

KevinKM said:


> Later this evening an operator complained of smoke coming from a MCC Panel. It seems that when he turned the main breaker on, it was shortly after that he noticed a smoke smell. He then opened the panel and observed smoke. I have not had a chance to investigate yet, will do that tomorrow. Just wanted to get some ideas on where to look. He did not push the start button for the pump to engage. This is a Cutler Hammer motor starter, soft start. It does contain a control transformer and industrial relay for the control circuit. Any help would be appreciated. Thanks in advance.


 
If I noticed smoke coming from an MCC, the LAST thing that I would do would be to open the door while it was energized. Kill the power to it, then investigate. What can go wrong, will go wrong. 

Me, personally, the cases that I have encountered of smoke coming from an MCC ended up being a fried coil on size 3 and 4 starters. I don't know how they put that much smoke in them from the factory, but it is a lot.

I know your original post was from a month ago, but as others have said, it is kind of hard to diagnose it without being right in front of it.


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