Siemens 8MR21702KA Enclosure Thermostat NC 0-60°C DIN Rail

In control cabinets and enclosures, precise temperature management prevents condensation and protects sensitive electronics. The Siemens 8MR21702KA enclosure thermostat regulates heating elements, switching them on when the temperature drops below the set point. Its normally closed (NC) contact opens as temperature rises, making it suitable for controlling heaters in industrial enclosures, telecommunication cabinets, and outdoor installations.

Key specifications

• Thermostat type: Normally closed (NC)
• Temperature setting range: 0 °C to +60 °C
• Switching difference: approx. 7 K (±4 K tolerance)
• Sensor element: Thermobimetal
• Contact type: Snap-action contact
• Switching capacity (AC): 250 V, 10 A (resistive); 2 A (inductive)
• Switching capacity (DC): 24 V, 10 A; 48 V, 5 A; 110 V, 2 A; 220 V, 1 A
• Mounting: DIN rail (35 mm) or screw mounting
• Connection: Screw terminals, max. conductor cross-section 2.5 mm²
• Protection class: IP20
• Housing material: Plastic (UL94 V-0)
• Colour: Light grey (RAL 7035)
• Operating temperature: -20 °C to +80 °C
• Storage temperature: -45 °C to +80 °C
• Humidity: max. 90% RH, non-condensing
• Approvals: VDE, UL, cUL

Why choose it

The snap-action contact ensures reliable switching with minimal wear, and the wide temperature range covers most enclosure heating applications. The compact plastic housing mounts quickly on standard DIN rails, and screw terminals accept conductors up to 2.5 mm² for secure connections.

Ideal use cases

• Control cabinet heating to prevent condensation
• Telecommunication outdoor cabinets
• Industrial automation enclosures
• Any application requiring NC thermostat control

Good to know

The thermostat is designed for use in dry environments (IP20). For inductive loads, the AC switching capacity is reduced to 2 A. The device is approved by VDE, UL, and cUL, ensuring compliance with international standards.