Engineering Construction procedures - 480V MCC replacement and addition

[Dale001289]

I have a couple scenarios and not sure how to proceed from a construction standpoint - in one substation, we're installing a new MCC in the same location as the existing MCC; in another substation we're installing a new MCC immediately next to an existing MCC, since space is available.

thoughts ???

 

[ron]

I have a couple scenarios and not sure how to proceed from a construction standpoint - in one substation, we're installing a new MCC in the same location as the existing MCC; in another substation we're installing a new MCC immediately next to an existing MCC, since space is available.

thoughts ???

Sounds good

 

[petersonra]

i don't know what your question is. personally, if I were the owner, I would want the old junk removed in both cases.

 

[Jraef]

i don't know what your question is. personally, if I were the owner, I would want the old junk removed in both cases.

To Bob's point, often times the old MCCs are going to be such that replacement parts or add-on buckets will only be available in the grey market, either as used/refurbished or from vendors who custom build them as aftermarket retrofit units using their brand of parts inside (Cutler Hammer does this) so you end up with a mash-up of different parts in the same lineup. All that can make any future replacement parts or buckets even more expensive than usual.

Also, the older MCC may be rated for a fault current determined BEFORE the new loads were added, which may have necessitated an increase in the service size and therefor the available fault current will be higher. Make sure you check all of the data on the old ones.

 

[gadfly56]

i don't know what your question is. personally, if I were the owner, I would want the old junk removed in both cases.

I'm guessing that in Scenario A that the MCC is still in use. How do you keep functionality during replacement? What about adjacent live equipment? I'm not sure what the issue is in Scenario B, but possibly you need to interrupt service from time to time or are encroaching on the 30" limit for adjacent equipment, etc.