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. With input voltage applied, the LED will be OFF. When the input from the hazardous area is closed, the output relay is energized and the LED is ON (Green). When the input switch opens, the output relay will de-energize and the LED will be OFF. Typical applications include pump lift stations, grain elevators, refineries and paint rooms.