# Are MCCs a thing of the past



## mburtis (Sep 1, 2018)

Just curious if they are still real prevalent. One plant we have from the 90s everything 3 phase is in an mcc, a lot of buckets are just breakers. The waste water plant has some old 1960s Chalmers (if I remember right) mccs that are just plain cool. Same deal there,basically everything is in an mcc. A lot of our newer stuff is a 3 phase panel with seperatly enclosed vfds or whatever.


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## micromind (Aug 11, 2007)

Not always true but the trend around here seems to be to use Motor Protection Circuit Breakers in the control panel for across-the-lines motors of 5HP and less. 

The PUCO around here will usually allow motors of 100HP (sometimes the limit is smaller though) to be started across-the-lines so if there's more than a few, it'll be in an MCC. 

I don't like VFD buckets in MCCs, I prefer to use a breaker bucket and mount the VFDs remotely.


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## SWDweller (Dec 9, 2020)

I agree that VFD's in buckets can be problematic. However if you stick with the Freedom series Eaton MCC's and have the buckets and doors enlarged for the MCC your a long way ahead. I used to get the basic MCC's from the California plant in Sulfur Springs but with the extended doors and buckets. There IS a place in Bid-manger to do that. You have to be a OEM or distributor to get BidMan. Can do panels and low voltage services as well. When I was estimating those jobs I would put the feed left right or in the middle and arrange the buckets any way the customer wanted them. Then purchase the Toshiba VFD's and have our guys do the installs. You can ever get fans installed in the doors for you VFD's something we paid for frequently here in the SW desert. 

These were nothing special MCC's no ladder busing or low voltage controls. Just standard stuff made all day long. 

If you have a friend at the supply house ask him about BidMan. Might be worth the trip to get exactly what you want the first time.


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## Flyingsod (Jul 11, 2013)

Just my two cents, I don’t think mcc’s are going away till drives are as cheap as contactors. There’s simply a lot of mechanical loads that don’t need a VFD. The bigger the motor the stupider it is to use a VFD when you don’t need one. Up to a point anyway. 


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## gpop (May 14, 2018)

Water and waste water plants are a bunch of separate items in a common area so mcc's make less sense. (E.g you buy a package's that comes with its own controls). Places that have mcc's tend to skip the package and just buy the machine. 
All of our new water/waste water plants have mcc's which works for us as we have our own programmers writing the code. Even then we still have lift stations in the general area that run on stand alone panels.

In the food industry i came from everything was mcc's as it was either wet or dusty. The last juice plant i work in had 8 mcc's and over 700 motors. It was nice working in a clean air conditioned room rather than sweating outside or having to set up a tent to keep the rain out.


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## micromind (Aug 11, 2007)

gpop said:


> Water and waste water plants are a bunch of separate items in a common area so mcc's make less sense. (E.g you buy a package's that comes with its own controls). Places that have mcc's tend to skip the package and just buy the machine.
> All of our new water/waste water plants have mcc's which works for us as we have our own programmers writing the code. Even then we still have lift stations in the general area that run on stand alone panels.
> 
> In the food industry i came from everything was mcc's as it was either wet or dusty. The last juice plant i work in had 8 mcc's and over 700 motors. It was nice working in a clean air conditioned room rather than sweating outside or having to set up a tent to keep the rain out.


A lot of MCC rooms around here are A/C only, no heat. 

Maybe if the brilliant engineers who decided on no heat had to work in one when it's 2º, they might think differently. 

Wait....engineer.....think....did I really say that????


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## JRaef (Mar 23, 2009)

MCCs have a major advantage over control panels. If you want to work on ONE device in a big control panel full of contactors, drives and breakers, you must de-energize the ENTIRE panel, or go through the rigmarole of getting an "energized work permit" signed off by every manager within driving distance. If the machinery must all run at the same time, that may not be an issue, but in a larger factory environment, it is. There is also a problem when it comes to LO/TO because even if you have individual protective switches that can be locked off, they usually don't have their handles extended through the doors, so again, you technically have to kill power, open the door, lock out the device, close the door, then restore power. An MCC allows you to turn off ONLY the starter / drive / breaker bucket that you need to work on, remove it, and let the rest of the equipment continue running. Despite people thinking that MCCs are "too expensive" compared to control panels, they often don't factor in the extra cost of down time.

Yes, I know many people ignore this aspect of our trade, but technically, you CANNOT work on energized equipment without risking CRIMINAL charges for the managers and supervisors that allow it to happen. That of course can be seen as a BONUS for some electricians, but nonetheless, technically that is the case.

Another advantage is that of "collateral damage" in that if a device fails catastrophically in a crowded control panel, it tends to take out it's neighbors as well.In an MCC, that damage is usually contained in the bucket.


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## gpop (May 14, 2018)

Nothing like sitting in the van waiting for the rain to stop knowing that the pump that is currently down is responsible for pumping the rain water down the system.


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## Flyingsod (Jul 11, 2013)

mistake


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## JRaef (Mar 23, 2009)

gpop said:


> Nothing like sitting in the van waiting for the rain to stop knowing that the pump that is currently down is responsible for pumping the rain water down the system.


I was once sitting in a pump station in Prescot Arizona while a wildfire was bearing down on us, trying to get a 600HP well pump started to help fight the fire... _that was bearing down on us_. I was there for the 900HP MV soft starter, but when we started it, they had forgotten to tighten an expansion joint on the pipe and it separated a tiny little bit, sending out a nearly invisible thin stream of high pressure water that could have cut a person in half had they walked through it. The water got into the controls and shorted things out, we literally went down to the local Dollar General and bought two hair blow dryers to dry it out. Luckily it worked. That was a fun day.


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## micromind (Aug 11, 2007)

JRaef said:


> Another advantage is that of "collateral damage" in that if a device fails catastrophically in a crowded control panel, it tends to take out it's neighbors as well.In an MCC, that damage is usually contained in the bucket.


I've seen this more than once..........

In a small panel, it often comes down to 'should I try to clean it up and replace only the bad parts or should I just gut the whole panel and start over'. 

In a larger panel it's usually only a half-dozen things that got wrecked so you're better off replacing some of it rather than all of it.


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## gpop (May 14, 2018)

micromind said:


> I've seen this more than once..........
> 
> In a small panel, it often comes down to 'should I try to clean it up and replace only the bad parts or should I just gut the whole panel and start over'.
> 
> In a larger panel it's usually only a half-dozen things that got wrecked so you're better off replacing some of it rather than all of it.


That's why you shove a copy of the prints, a programming manual and a bunch more paper down the side of the starters. No more guessing if its a repair or a complete gut.


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## Majewski (Jan 8, 2016)

i hope they are a thing of the past. last one i touched bit me...and it really really hurt.


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## micromind (Aug 11, 2007)

gpop said:


> That's why you shove a copy of the prints, a programming manual and a bunch more paper down the side of the starters. No more guessing if its a repair or a complete gut.


That's a great idea! No more guesswork.......if the paint on top is bubbled up, no question......complete rebuild!


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## Majewski (Jan 8, 2016)

micromind said:


> That's a great idea! No more guesswork.......if the paint on top is bubbled up, no question......complete rebuild!


maybe i shouldnt go at them so aggressively with a huge beater


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## mburtis (Sep 1, 2018)

micromind said:


> That's a great idea! No more guesswork.......if the paint on top is bubbled up, no question......complete rebuild!


Nah that just means you have to go the store for a wire brush and spray paint.


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## Quickservice (Apr 23, 2020)

micromind said:


> Not always true but the trend around here seems to be to use Motor Protection Circuit Breakers in the control panel for across-the-lines motors of 5HP and less.
> 
> The PUCO around here will usually allow motors of 100HP (sometimes the limit is smaller though) to be started across-the-lines so if there's more than a few, it'll be in an MCC.
> 
> *I don't like VFD buckets in MCCs, I prefer to use a breaker bucket and mount the VFDs remotely.*


All the VFD's I ever messed with were installed exactly like this.


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## paulengr (Oct 8, 2017)

mburtis said:


> Just curious if they are still real prevalent. One plant we have from the 90s everything 3 phase is in an mcc, a lot of buckets are just breakers. The waste water plant has some old 1960s Chalmers (if I remember right) mccs that are just plain cool. Same deal there,basically everything is in an mcc. A lot of our newer stuff is a 3 phase panel with seperatly enclosed vfds or whatever.


VFDs do not do well in MCCs because of major cooling issues. They can be mounted side by side but need lots of top to bottom air flow so they are much better off either mounted on a back plate in open air or in a well ventilated cabinet or in the flange mount style where the power side projects out the back. Plus retrofitting is usually pretty straightforward. Remember that a VFD has a 100,000 hour design life (don’t believe Eatons crazy reliability claims…they fail at the same rate as everyone else). If it survives that solder joints fail at around 15 years, and this assumes good air flow and temperatures and no environmental problems (excessive oil or moisture, dust, lint, hydrogen sulfide, acids, alkalis). This is far less than the 25 year design life of an MCC and most of those often make it to 30-40 years.

MCCs are best used with lots of 10-250 HP starters. On the smaller sizes it is far less expensive and easier to maintain with DIN rail mounted starters in an industrial control panel. Above 250 HP you can get an “MCC” starter but it’s MCC in name only. The starter is effectively in an MCC-styled box. It can just as easily be in a separate enclosure fed from a breaker such as from a panel board or switchboard.

If you stick to the “sweet spot” for an MCC and minimize the amount of other stuff that becomes overpriced (breakers, small starters) or add on huge “engineering” costs and time (VFDs, PLCs, distribution panels, large starters, etc.) MCCs are very inexpensive and don’t take up a lot of space. But the more you deviate outside of this design space the faster you will “blow up” MCC costs and space.

In addition in very old plants I’ve seen a lot of troughs with NEMA combination starters. This is cheap for a few starters even today. For higher density and later on the MCCs dominated. They were still NEMA but everything was modular and compact. Today breakers have continued to shrink in size but the big change is the transition to IEC starters with various breaker and overload options. An even more compact design especially with smaller motors is a “type F” starter that has an MMS with integrated bimetallic or RC overload and an IEC contactor close mounted to it, stuffed into an industrial control panel with bus bar strips for power, or breakers feeding VFDs.

Another consideration is the NEC “within sight of” disconnect requirement. At one time the best option was the NEMA heavy duty (480 V) disconnect and these cost more than the MCC buckets! Or to exercise the on site maintenance exception. Now IEC style field secondary disconnects are cheap so there is less financial incentive to avoid them. So one of the limitations with industrial control panels is that most often ALL motors must be locked out because there is a single lockout point. The secondary disconnects remove this limitation that is not a factor with MCCs where each motor can be independently locked out.

So I don’t think MCC is outdated. It’s just that the “sweet spot” just isn’t that large.


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