Allen-Bradley 1512B, User Manual

Page: 78 / 108

78 Rockwell Automation Publication 1500-UM055I-EN-P - December 2021
Appendix A ArcShield Unit Information
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 plenum 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 69 - Elements of ArcShield Plenum