Tapping a MCC

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Possibly. It will depend on ampacity of bus being tapped, length and ampacity of tap conductors, location tap is made on MCC bus, and also any considerations that may affect the listing of the MCC.

In short, more information is needed.

Pete
 
Wouldn't making the tap be a violation of article 430.10 and 430.97? If the section of MCC was not designed for a tap section, then the tap wasn't intended to be there.

430.10 Wiring Space in Enclosures.
(A) General. Enclosures for motor controllers and disconnecting means shall not be used as junction boxes, auxiliary gutters, or raceways for conductors feeding through or tapping off to the other apparatus unless designs are employed that provide adequate space for this purpose.


430.97 Busbars and Conductors.
(A) Support and Arrangement. Busbars shall be protected from physical damage and be held firmly in place. Other than for required interconnections and control wiring, only those conductors that are intended for termination in a vertical section shall be located in that section.

Rick
 
You would be altering a piece of LISTED equipment. Doing so might not hurt a thing, but it places some liability on you in the event of any problem.
You might contact the manufacturer and see if they have any input
(they are usually reluctant to approve and field changes and when they do they often want a field evaluation).
 
I've seen taps on buss bars. They LLS. I recently asked SQD for something that would allow to do this in a nice legal professional manner. Nope. No way. Don't even think about. Correct part for what i needed or wanted was something like $18K. Not lugs on buss bars either.
 
I think you can do anything you want as long as the manufacturer gives the OK. We've tapped a Siemens switchboard to add a 1200 amp GFI breaker out of it and they were OK with it.

Since this is an MCC, I assume you don't have space for another bucket? Can you consolidate some loads into some half space factor buckets to make room for your feeder bucket?
 
weressl said:
Why would you tap? Install a feeder breaker bucket. That is what is available for that purpose as a standard offering from all MCC manufacturer. Just because it is called M(otor)C(ontrol)C(enter) it does not mean that it only feeds motors.
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I agree. It will be the simplest answer and is usually the least expensive solution available. Tapping directly to the MCC bus is kind of iffy in my mind, although it seems to happen now and then.

I seem to recall AB actually has a kit available for doing just this, but I might be remembering wrong.
 
petersonra said:
I agree. It will be the simplest answer and is usually the least expensive solution available. Tapping directly to the MCC bus is kind of iffy in my mind, although it seems to happen now and then.

I seem to recall AB actually has a kit available for doing just this, but I might be remembering wrong.
Click to expand...

You remember correctly Bob.

The AB tap kit is available for 400A and above breakers, but it is not UL listed, therefore the installation of it would void the MCC listing. (If you get the AHJ agree, you can be scott-free.)
 
Tap the feeder supplying the MCC. Better yet just branch off of it with full sized feeder and you will have a place to tap more loads in the future - assuming you have ampacity available to take on more load
 
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