Generic KSD9700/BK05-BB1D 155°C Temperature Control Switch - 5A 250V AC, Normally Open, Metallic Shell

This specific model, KSD9700/BK05-BB1D, is a Normally Open (NO) switch. The contacts are open at room temperature and will remain open until the calibrated temperature of 155°C is reached, at which point the mechanism snaps to maintain the open state as a safety cutoff. It does not close the circuit upon overheating.

The switch is rated for a maximum of 5 Amps at 250 Volts Alternating Current (AC). This rating is for resistive loads; for inductive loads like motors or solenoids, derating may be necessary to account for inrush current. Do not exceed these ratings to ensure safe operation and prevent contact welding.

Install the switch by firmly mounting its metallic shell to the heat source (e.g., motor housing, transformer core) using the provided bracket or thermal adhesive to ensure good thermal transfer. Wire it in series with the load (e.g., heater coil) and the power source. The two terminals are not polarized; connect one to the incoming power and the other to the load.

No, it does not reset automatically. It is a manual-reset, non-latching type switch. Once it trips open at 155°C, the circuit remains broken. You must disconnect power and allow the switch and the protected device to cool down significantly below the trip temperature before the bimetallic disc will snap back, closing the contacts to restore circuit operation.