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Rockwell Automation Publication 2100-IN012G-EN-P - August 2016
Chapter 1
General Information
Line power is distributed throughout the MCC via an isolated bus work
structure. The main horizontal bus is in the center of each section. Standard,
center-fed, 300 A rated vertical bus supplies power to the individual units
above and below the horizontal bus for an effective 600 A capacity, providing
virtually unrestricted unit arrangement. An optional 600 A vertical bus
provides 1200 A effective rating.
The CENTERLINE MCC is also available with an ArcShield™ rating. The
ArcShield rating includes arc-resistant features that are intended to help
provide enhanced protection to you during internal arcing faults (when
compared to MCCs that are designed only to meet UL 845 requirements).
Arcing faults can be caused, for example, by accidental touching, closing into
faulted lines, or loose connections. Depending on the application, MCCs with
the ArcShield rating can provide up to Type 2 accessibility per IEEE standard
C37.20.7, which helps protect you when you are at the front, sides, and rear of
the enclosure in the unlikely event of an arcing fault.
A label on the MCC with the ArcShield rating provides information in regard
to the accessibility level and arc fault ratings.
For more information about accessibility levels, performance, and testing
requirements, refer to IEEE standard C37.20.7, IEEE Guide for Testing Metal-
Enclosed Switchgear Rated up to 38 kV for Internal Arcing Faults.
MCCs with the ArcShield rating provide a reinforced structure and arc-
containment latches on all doors. To help protect you during an arc-fault, arc-
containment latches, when closed and latched properly, provide pressure relief
and help keep the doors from unlatching or detaching from the structure.
Nameplate Data
Each MCC section has a nameplate on the enclosure or vertical wireway door.
The nameplate includes the following information:
• Catalog number/serial number
• Series letter of section
• Bus bar voltage and current rating
• Section number
• UL and cUL certification marking
• UL registration number
• Enclosure type
Figure 1 - Section Nameplate