KSD9700/BK05-BB1D Metallic Shell Temperature Control Switch - 110°C Normally Open, 5A 250V

This thermal switch is configured as Normally Open (NO). The contacts are open under normal, cool conditions and physically close to complete the circuit only when the sensed temperature reaches the calibrated set point of 110°C. This design is typically used to activate an alarm, fan, or shutdown sequence when overheating occurs.

The switch is rated for a maximum current of 5 Amps at a voltage of up to 250 Volts AC or DC. This rating allows it to directly switch smaller loads like fans, solenoids, or indicator lights without an external relay. For loads exceeding 5A, it must be used to control the coil of a suitably rated relay or contactor.

Mount the metallic shell of the switch directly to the component or surface you wish to monitor (e.g., a transformer case or heatsink) using thermal adhesive or a mechanical clamp to ensure good heat transfer. Connect the two integrated 7cm lead wires in series with your load or control circuit. The switch will act as a closed circuit only when its temperature reaches 110°C.

The KSD9700 series typically uses a bimetallic snap-disc mechanism, which is often a one-time, non-resettable device. Once it activates at 110°C, the contacts close permanently, requiring replacement of the unit. Confirm the specific model's datasheet for its reset behavior, but this variant is generally designed for irreversible safety cutoff.