User Generated Control Drawings for Intrinic Safety

[bobdoug]

Is it acceptable to connect a non-rated 24 VDC powered, 4-20 ma signal output load cell to an appropriate barrier, to meet Class I, Div 2 Group B Intrinic Safety requirements provided that the entity paramaters, wiring, etc. is documented on a user generated control drawing? The load cell itself does not have a control drawing or IS certification and is not capable of being located in a purged enclosure. If generating a user control drawing is not an acceptable practice are any other options avaialbe for this hazard area.

 

[rbalex]

Is it acceptable to connect a non-rated 24 VDC powered, 4-20 ma signal output load cell to an appropriate barrier, to meet Class I, Div 2 Group B Intrinic Safety requirements provided that the entity paramaters, wiring, etc. is documented on a user generated control drawing? The load cell itself does not have a control drawing or IS certification and is not capable of being located in a purged enclosure. If generating a user control drawing is not an acceptable practice are any other options avaialbe for this hazard area.

A control drawing, whether for intrinsically safe (IS) or nonincendive (NI) systems, is by definition generated by the appropriate apparatus' manufacturer. [See the definition in Section 500.2] A manufacture's control drawing for the barrier itself may be sufficient. BTW, you only need NI in Division 2.