UL 698A Question for a Class 1 Div 2 Location

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Chris B

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Pensacola, FL
Hi- I have a control panel mounted in a non classified area with extensions into a Class 1 Division 2 area. FYI- The classified area has gasoline vapor recovery equipment on a remediation (gasoline spill) site... My question is this: If the panel has extensions to a Class 1 Div 2 location, does the panel need to comply with UL 698A standards and have intrinsic barriers in place between control equipment (PLC) and devices /sensors which are located within the piping of the recovery process? I see in the UL698A Scope, it mentions Class 1 DIV 1 but not Div 2...

Thanks in advance for any help!
 
As long as the panel is in an unclassified location and proper wiring methods are used (conduit/cable seals as required in Art 501) then a standard UL508 panel is fine. You only need IS barriers if IS equipment/circuits are being supplied from the panel. It is quite common.
 
Thanks. So what determines the need for the use of IS barriers? I am under the impression that any control circuit that has extensions into a classified area needs to have an IS barrier or be a nonincendive device and wired appropriately.

Thanks again.
 
Typically all kinds of pushbuttons, indicator lights, transmitters etc are in located inside C1D1 or C1D2 locations. It is common in large facilities to have central control panels in control rooms that feed these circuits. IS may be used in these and NI may be used in C1D2 but are not required to be used. The equipment has to be listed for the location and the proper wiring methods used, but I know of no SHALL USE for IS & NI. Think of it this way- why would you be required to have an IS or NI for a control circuit when you can run 480V 3 Phase power to various equipment and have power circuits to lights, receptacles, alarm horns, motors etc. If you are using IS circuits then you need to follow Art 504 and there are separation requirements in the panel from non-IS circuits. A typical 4-20mA Pressure transitter or Control Valve actuator does not require IS or NI although there are several that are rated NI if used according to the NEC requirements.
 
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