MCC/Switchgear Retrofit

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Designer69

Senior Member
Good morning gents,

what kind of devices can I retrofit MCC or Switchgear cubicles with? are there any limitations?

i.e., can I pull out a motor starter from an MCC bucket and install a fused disconnect switch in its place?

or can I pull out a protective relay from a switchgear cubicle and install a circuit breaker?

Thanks!
 
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Designer69

Senior Member
because there is an MCC cublicle with a motor starter powering a large fan motor.

the fan motor load got demo'd and we want to use that MCC bucket to power a spot welder.

so can I remove the motor starter and install a fused disconnect switch in its place?
 
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BJ Conner

Senior Member
Location
97006
IME if you buy the fitted bucket from the MCC vendor ( or have it configured by thier local service shop ) no problem.
If you assemble it your self from parts you have and it looks like the same thing they have in their catalog. Probably not a problem.
The maintenance/service manuals for most MCCs cover doing that kind of work. I have never had an inspector object. Your putting together a compinent that is listed and doing so in accordance with the manufactures directions.
Revise the MCC drawings and one-line to show you have got a handle on what your doing. Recheck the load calcs on the MCC and upstream.
 
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rcwilson

Senior Member
Location
Redmond, WA
If you can find a fused disconnect switch made by the manufacturer of the MCC, you could pull the motor starter and plug in the switch bucket. You will violate the listing of the equipment if you try to scab a fused switch into the space.

I haven't seen many MCC buckets with fused switches for feeders. Most use circuit breakers so you may have a hard tie finding one.

If the existing motor starter is a combination starter with a fused switch or a circuit breaker, not a magnetic only motor circuit protector that looks like a circuit breaker, you might be able to pull the contactor and overloads out and use the starter bucket as a feeder.

Your question on switchgear is confusing. Are you talking about a protective relay mounted on a compartment door of a 480 V switchgear cubicle that doesn't have a circuit breaker? I'm guessing you want to put a breaker in that cubicle. If so, the answer is probably no, unless the manufacturer equipped that cubicle with the bus work for future installation of a breaker. Usually any space with relays is dedicated only to low voltage wiring and control equipment.
 
zog

zog

Senior Member
Location
Charlotte, NC
Designer69 said:
because there is an MCC cublicle with a motor starter powering a large fan motor.

the fan motor load got demo'd and we want to use that MCC bucket to power a spot welder.

so can I remove the motor starter and install a fused disconnect switch in its place?
Click to expand...

Depends on the MCC make and model, you can use a fuesable feeder bucket or a breaker style. I have plenty of them :)
 
zog

zog

Senior Member
Location
Charlotte, NC
rcwilson said:
If the existing motor starter is a combination starter with a fused switch or a circuit breaker, not a magnetic only motor circuit protector that looks like a circuit breaker, you might be able to pull the contactor and overloads out and use the starter bucket as a feeder.
Click to expand...

True, that would be the first thing to check.

rcwilson said:
Your question on switchgear is confusing. Are you talking about a protective relay mounted on a compartment door of a 480 V switchgear cubicle that doesn't have a circuit breaker? I'm guessing you want to put a breaker in that cubicle. If so, the answer is probably no, unless the manufacturer equipped that cubicle with the bus work for future installation of a breaker. Usually any space with relays is dedicated only to low voltage wiring and control equipment.
Click to expand...

That is the part I was confused on too. But it is often easy enough to add another vertical section to existing gear.
 
Jraef

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Actually the first question to ask yourself is, "Is UL listing important to me, or my insurance underwriter?"

If the answer is yes, then the rest is moot. You cannot manufacture your own buckets or alter the contents of an MCC bucket or a Swgr cubicle without violating the UL listing. Not only the individual unit, but the entire line-up gets voided if you install a non-listed unit as well. You can ADD a bucket or cubicle if you order it from the factory (or another properly UL listed source), but you cannot do it on your own. For MCC buckets, the source must be listed under UL845 for that exact brand and model of MCC. For "Switchgear" it would be dependent on the type of gear, i.e. UL891 for Switchboards, UL1558 for Switchgear and UL869A for Service Equipment

If UL listing is not important to you and you are not going to get it inspected, you can get away with lots of things, but don't expect support from the mfr. and double check your insurance policy on what happens if they find out in a fire investigation. (hint: it usually results in them weaseling out of paying for it)
 
weressl

weressl

Esteemed Member
Location
Texas by the Gulf, geat crab, great shrimp
Jraef said:
Actually the first question to ask yourself is, "Is UL listing important to me, or my insurance underwriter?"

If the answer is yes, then the rest is moot. You cannot manufacture your own buckets or alter the contents of an MCC bucket or a Swgr cubicle without violating the UL listing. Not only the individual unit, but the entire line-up gets voided if you install a non-listed unit as well. You can ADD a bucket or cubicle if you order it from the factory (or another properly UL listed source), but you cannot do it on your own. For MCC buckets, the source must be listed under UL845 for that exact brand and model of MCC. For "Switchgear" it would be dependent on the type of gear, i.e. UL891 for Switchboards, UL1558 for Switchgear and UL869A for Service Equipment

If UL listing is not important to you and you are not going to get it inspected, you can get away with lots of things, but don't expect support from the mfr. and double check your insurance policy on what happens if they find out in a fire investigation. (hint: it usually results in them weaseling out of paying for it)
Click to expand...

Often the MCC sections are listed as individual vertical sections, not as an entire assembly and the cubicles are individually listed. Depends on how the listing is written for the vertical section, eg. it restricts the installation within to listed and specifically enumerated components an unlisted bucket, or any other unlisted component, may or may not void its own listing.

The insurance companies are finding that often the non-paying excuses are refused by juries when the excuse has nothing to do with the actual damage. Ex. if you changed a component within the bucket and an unrelated failure caused the vertical section to fail the claim may made to stand. On the other hand if in the same case OSHA cites you for general violation then the OSHA fine stands.
 
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