Rockwell Automation MV SMC Flex Motor Controller (for Series K or later) - Manual (Page 189)

Rockwell Automation Publication 1560E-UM051F-EN-P - June 2013 179
Appendix
D
ArcShield Unit Information
Overview ArcShield units have a robust arc resistant enclosure design that has been tested
per IEEE C37.20.7 (2001). Each ArcShield structure was tested to withstand the
effects of an arc flash at 40 kA for 0.5 seconds. ArcShield units provide an
enhanced Type 2 Accessibility level.
ArcShield Design
ArcShield units typically include a pressure relief vent on the roof of the structure
(some incoming units may not have a pressure relief vent if top cable entry is
required). Under arc flash conditions the pressure relief vent will open allowing
hazardous flames and gases to exit the enclosure via plenum or chimney system.
The low voltage panel area is sealed to prevent flames and gases from entering;
however, suitable personal protective equipment (PPE) must be used whenever
working on live circuits.
ATTENTION: To ensure Arc resistant integrity, it is important to ensure that the
following rules are followed:
• The pressure relief vent may not be tampered with, and it is not to be used as a
step.
• No alterations can be made to the ArcShield structure.
• All covers, plates and hardware removed for installation or maintenance
purposes must be re-installed and properly secured. Failure to do so voids the
arc resistant integrity.
• Power cable entry points are to be treated as the boundary between a
hazardous location and sealed accordingly. Failure to do so voids the arc
resistant integrity.
• A plenum or chimney must be used to direct the arc flash energy to a suitable
location. Failure to do so voids the arc resistant integrity. Refer to Appendix E
for plenum installation instructions. Refer to Appendix F for chimney
installation instructions.
• All wiring between the low voltage panel and the power cell must be routed
through a suitable gland to ensure flames and gases are not transmitted into
this area (as fitted from factory).
• The medium voltage power cell doors must be properly secured, using both the
handle mechanism and the door bolts (refer to instruction label on the power
cell door and in Chapter 2). Failure to do so voids the arc resistance integrity.