Rockwell Automation 1512A MV Controllers - 800A One-High Cabinet - Manual (Page 77)

ArcShield Unit Information A-3
1512A-UM102B-EN-P – June 2013
Exhaust Systems: Chimney or Plenum Option
Plenum Information
A plenum can be provided for each unit, and is to be field-mounted on
the top of the unit structure (some incoming units may not have a
plenum if top cable entry is required). The purpose of the plenum is to
direct the hazardous flames and gases away from the top of the arc
resistant enclosure. Unit plenums are secured to the top of the unit
structure and to adjacent plenums, creating a continuous conduit for
release of the arc flash energy. Refer to Appendix B for plenum
installation instructions.
Each ArcShield line-up includes a plenum exhaust section that extends
beyond either the left or right ends of the line-up. The other end of the
plenums is capped with an end cover. Extensions can be added to the
plenum to allow the arc flash energy to be directed further away from the
ArcShield line-up to an area where safe venting of the plasma gases can
occur.
Figure A.1 – Elements of ArcShield Plenum