The ISP series of Intrinsically Safe Relays provide a safe and reliable method to control a load (motor starter, relay, etc.) with an input device (switch, sensor, etc.) located in a hazardous area. The Instrument Society of America defines intrinsically safe equipment & wiring in their specification ISA-RP12.2 as: "equipment and wiring which is incapable of releasing sufficient electrical or thermal energy under normal or abnormal conditions to cause ignition of a specific hazardous atmospheric mixture in its most ignited concentration. Intrinsically safe terminations and wiring may be brought into any hazardous location of any Group classification for which it is accepted without requiring explosion-proof housing or other means of protection”.
UL Listed apparatus provides intrinsically safe circuits for use in Class I Groups A, B, C, D, Class II Groups E, F, G, and Class III Hazardous Locations. The ISP relay must be mounted in a non-hazardous area,following Macromatic Control Drawing Number ISR2A01D. In order to comply with UL requirements, intrinsically safe and non-intrinsically safe wiring must be physically separated to prevent inadvertent bypass.
Each ISP relay consists of an intrinsically safe control switch input and an electromechanical relay output. When the control switch in the hazardous area is closed, the relay is energized. When the control switch is opened, the relay is de-energized.
Typical applications include pump lift stations, grain elevators, refineries and paint rooms.
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