Thermostat sensor SPST-NC 90°C 16A 250VAC – bimetal temperature switch

SPST-NC 90°C 16A 250VAC – bimetal temperature switch is a single-pole, single-throw normally-closed thermostat sensor designed to open when the ambient or contacted surface temperature reaches approximately 90°C. Built around a bimetallic element, this temperature switch provides a mechanical open/close action for overtemperature protection and basic control functions in appliances, heating, ventilation and air conditioning (HVAC) systems, and a variety of industrial devices.

Advantages

The bimetal design offers dependable, repeatable switching at the rated trip temperature without requiring external power for sensing, ensuring fail-safe operation in many thermal protection applications. With a rated switching current of 16 A at 250 VAC, the switch can handle resistive and moderately inductive loads typical for heaters, fans and motors. The normally-closed (NC) contact arrangement provides power continuity until the defined temperature threshold is reached, simplifying integration into safety and control circuits. Its compact mechanical construction enables installation in tight spaces and straightforward replacement of legacy thermostat sensors.

Suitable for

• Overtemperature protection in household and commercial appliances (heaters, ovens, dryers)
• Temperature control and safety cut-off in HVAC units and fan assemblies
• Thermal protection for electric motors, transformers, and industrial control panels
• Backup overheat cut-out in laboratory and process equipment

Key specifications

• Switch type: SPST (single-pole, single-throw), normally-closed
• Trip temperature: 90°C (approximate operating point)
• Rated current: 16 A at 250 VAC
• Sensing element: bimetallic disc for mechanical snap action
• Contact action: mechanical open/close (no electronic sensing)
• Typical mounting: panel or chassis mount compatible with standard thermostat housings

How to use

Install the thermostat sensor so the bimetal element is exposed to the medium or surface whose temperature you need to monitor, following the mechanical mounting arrangement required by your equipment. Wire the device in series with the load or control circuit, observing the SPST-NC contact configuration so the circuit is closed under normal temperatures and opens at the trip point. Verify that the connected load current and voltage do not exceed 16 A at 250 VAC. After installation, perform functional testing by raising the local temperature to confirm the switch opens near 90°C and resets as the temperature falls to the device’s release temperature.

Usage recommendations

Use the switch for thermal protection and basic on/off temperature control where precise electronic regulation is not required. Avoid exposing the switch to corrosive atmospheres, excessive vibration, or continuous temperatures above the rated trip range. For inductive loads or frequent cycling applications, add appropriate suppression or use a relay to extend contact life and ensure reliable operation.