MCC Work

[Alwayslearningelec]

Is there a lot of work involved in this? When someone says "bucket" is that just a section or specific OCPD device? Where did that term originate?

 

[Jraef]

MCCs consist of multiple vertical 90” high “sections”, each section has 72” of mounting height for “units”, divided up into “space factors” defined by 12” in height, so there are 6 full space factors in each section, and most manufacturers also divide it further by “1/2 spaces” of 6 inch increments. A unit then can be any number of space factors, and up to a certain size, usually 4 space factors max, the units can be plugged into the bus or removed from it. Removable units are often referred to as “buckets” because when you remove them, there is (typically) a full 5 sided box (the door remains on the section) that resembles a bucket containing the bus stab assembly, the disconnect/OCPD, then any power control device (starter, soft starter, VFD, lighting contactor) that might also be included. But if there is no power control device in the bucket, it is referred to as a “Feeder”.

Larger than 4 space factors generally results in “fixed mounted” units, meaning they are bolted in and bolt connected to the bus, so they are not removable.

 

[Alwayslearningelec]

Thank you very much.

 

[jim dungar]

Larger than 4 space factors generally results in “fixed mounted” units, meaning they are bolted in and bolt connected to the bus, so they are not removable.

Or they may be cable fed from a different feeder bucket, in which case the unit doors are usually interlocked.

 

[Alwayslearningelec]

You guys are so incredibly knowledgeable. Wish I would've done the electrician thing for at least 5 years instead of jumping right into the office.