The Sensata Dominican REP (or Mexico depending on where made) RP1B is a thermal protector* for lighting fixtures. It has a dedicated voltage of 120Vac and has low sensitivity. It has three leads, black, white, and blue. When the temperature of the fixture is exceeded it will cause the light to blink. It is auto resetting for when the fault is corrected. The Sensata RP1B is designed to fit into a 1/2" KO.
The black lead wire is always connected to the input live wire The white wire is the common which is permanently connected at the factory with an extra six inch piece of wire of the same color The third wire of the RP is permanently connected to the live side of the load
The Sensata RP-1B thermal protector is a critical safety component specifically engineered for recessed lighting fixtures, functioning primarily as an insulation detector to prevent hazardous overheating. This automatic resetting device is designed for 120V applications and features a low-sensitivity bimetallic strip that monitors the thermal environment within a luminaire. When internal temperatures exceed safe operating limits—often due to the presence of insulation or overlamping—the RP-1B interrupts the circuit, causing the light to blink as a visual warning to the user. This "blinking" fault condition continues until the temperature drops below the trip point, at which time the device automatically resets. Built with a compact three-wire configuration black, white, and blue leads, it is recognized under UL 873 and is essential for maintaining compliance in non-IC (Insulation Contact) rated housings, ensuring that residential and commercial lighting systems remain fire-safe.