Receptacle and Attachment Plugs

[filterengineer]

I'm a bit confused regarding Section 502.145 of NEC 2011. I have both Class II Div 1 and Div 2 locations at my facility.


For Div 1, the code states "receptacles and attachment plugs shall be of the type providing for connection to the equipment grounding conductor of the flexible cord and shall be identified for Class II locations".

For Div 2, the code states "receptacles and attachment plugs shall be of the type providing for connection to the equipment grounding conductor of the flexible cord and shall be designed so that connection to the supply circuit cannot be made or broken while live parts are exposed".

To me, the Div 1 requirement is straightforward.....I simply specify products that are identified for Class II locations. However, the Div 2 requirement is not obvious to me. What does it mean by "that connection to the supply circuit cannot be made or broken while live parts are exposed"? Is a standard 120V grounded outlet acceptable?

I appreciate any clarification that can be provided.

Thanks

 

[rbalex]

...
... However, the Div 2 requirement is not obvious to me. What does it mean by "that connection to the supply circuit cannot be made or broken while live parts are exposed"? Is a standard 120V grounded outlet acceptable?

I appreciate any clarification that can be provided.

Thanks

CMP14 accepts the definition of exposed(as applied to live parts) in Article 100. Effectively, a "standard 120V grounded outlet" meets this as the line and neutral are "isolated" while the EGC is made/broken. I still prefer a "twist-lock" connection, especially in Group F where the dusts may be conductive. (Group E is always Division 1)