Voices: Real Answers

Are purged enclosures and intrinsically safe barriers necessary?

How do I reduce wiring between hazardous and nonhazardous areas?

By Mike Bacidore
Jan 15, 2019

A Control Design reader writes: Our facility processes propellants and explosives with many areas classified as hazardous—Class II, Div. 1. Normally, we install the controller and I/O in a suitably purged enclosure and use intrinsically safe barriers for most field device connections. I'm not sure this is the best solution on a large canister-filling project, where there are nearly 500 I/O points on the hazardous-area automation. Because of the large installation and space limitations in the hazardous area, the main control panel will need to be located outside the hazardous area. How do I keep from running more than 500 wires, about 70 ft each, between hazardous and nonhazardous areas? What are my options?

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