Aging Motor Control Centers - Replace??

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scrub12

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Location
Cleveland, OH
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Electrical Engineer
I have multiple 480V 800A-1200A Motor Control Centers by various vendors. They range from 25 to 45 years old. Old GE Style MCCs, Model 4 Square D MCCs, etc. Is there an NFPA or IEEE or any other recommendation on when MCCs should start to be replaced? I know at some point getting buckets for these are going to be an issue if not already. Some MCC engineers I've spoken with have said typical lifespan is 25-40 years depending on environment and maintenance. Anyone know if some good reference literature I can point to do make my case to replace? Thanks in advance!
 
There are multiple companies that can make listed buckets for obsolete MCCs. Unless you have an issue with the vertical bus, all of the other parts of the buckets are easily replace able. The plant I spent a lot of time working in was built in the mid 60s, and most of the GE 7700 MCCs that were originally installed are still in use.

They did have a few issues with the vertical bus to bucket stab connections where they used size 3 or 4 plug in starters. We either moved the bucket up or down 6" to get to a new bus connection or replaced the bus. We always had replacement bus around because any time we needed to buy 2 or 3 buckets, it was cheaper to buy a whole section and take the buckets out of the new section and install them in the existing MCCs.
 
Agreed. An mcc is one of those things that will last indefinitely if maintained. Kind of like switchgear.

About the only issue I have seen is sometimes they have been installed in areas that are damp or maybe have some corrosive vapors.
 
And the custom made and listed buckets from third party manufactures are not always excessively expensive. I had a case where I needed a couple of buckets for the 7700 line and the price from a 3rd party was less than from GE and the delivery was better.
 
petersonra said:
About the only issue I have seen is sometimes they have been installed in areas that are damp or maybe have some corrosive vapors.
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Like these? That is mold and some little mushrooms growing on the VFD! It was still running though.
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Actually, these are less than 20 years old, but they put NEMA 1 MCCs in a hose down location, they just told the cleaners to not spray directly on the MCCs... Onion and garlic powder processing plant, the organic dust + moisture + dark + warm environment created a little mushroom farm!
 
There are no industry standards for this, but a general concept that is put into a lot of specifications will call for a design life of a minimum of 30 years, so most MCC manufacturers (all that I have ever dealt with) accept this spec requirement without comment. You could therefore infer from this that the lifespan is AT LEAST 30 years. The advent of VFDs, PLCs and other electronics inside of MCCs has likely changed that, because even 20 years is a long time for a VFD now.

Allen Bradley MCCs are still backward compatible to their very first ones they made in 1971. A few years ago I put an new bucket into an MCC at a US Steel plant that I had installed as an apprentice when I worked there in 1978; that's approaching 50 years in service now.
 
Thanks. All.

I did find a good reference article on IEEE's website titled, "Vintage Low-Voltage Mtoro Control Centers - Replace or Upgrade?". It echoes everyone's thoughts above.
 
Jraef said:
There are no industry standards for this, but a general concept that is put into a lot of specifications will call for a design life of a minimum of 30 years, so most MCC manufacturers (all that I have ever dealt with) accept this spec requirement without comment. You could therefore infer from this that the lifespan is AT LEAST 30 years. The advent of VFDs, PLCs and other electronics inside of MCCs has likely changed that, because even 20 years is a long time for a VFD now.

Allen Bradley MCCs are still backward compatible to their very first ones they made in 1971. A few years ago I put an new bucket into an MCC at a US Steel plant that I had installed as an apprentice when I worked there in 1978; that's approaching 50 years in service now.
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That was one thing I liked about the GE 7700 and 8000 lines...100% interchangeable....but that all changed with the 9000 line...totally different design.
 
zbang said:
That's the key- keep 'em clean and dry in a clean and dry room and do the recommended maintenance when it's due. (To be fair, that's a good plan for most equipment.)
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Hi, what would the recommended maintenance for a 1968 vintage GE 7700 be? I haven't been able to find anything online from GE other than parts list. In absence of manufacturer recommendations for inspection/maintenance schedule, would NFPA70e specify what an inspection should be and at what frequency? Also, for this question, should I qualify by saying beyond IR imaging? Thanks in advance. Not an electrician. I oversee EH&H on a college campus.
 
Campus safety said:
Hi, what would the recommended maintenance for a 1968 vintage GE 7700 be? I haven't been able to find anything online from GE other than parts list. In absence of manufacturer recommendations for inspection/maintenance schedule, would NFPA70e specify what an inspection should be and at what frequency? Also, for this question, should I qualify by saying beyond IR imaging? Thanks in advance. Not an electrician. I oversee EH&H on a college campus.
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IMO, IR imaging is mostly worthless as done by most places.

I think it is only useful to do when things are running at close to full load and then mostly as a comparison to previous scans, although by random chance you might see a hot spot that is worth investigating. But most electricians get nervous if something is warm to the touch and a lot of electrical items can get warm enough you don't want to touch them and be perfectly OK.

I think NETA has some standards for this kind of thing.

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