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Thermal Cutoff Technology

Thermal cutoffs are reliable thermal protection devices designed to protect home and industrial electrical appliances from catching fire due to overheating. The high quality standard of our thermal cutoff technology has been recognized by many international standards and are manufactured in factories that have been certified by the International Standards Organization (ISO9001/14001 quality standard).


Thermal cutoff devices are integrated into the electric circuit of appliances where temperature detection is required. The current is conducted in the device through an internal mechanism containing a thermal pellet made of an organic material or fusible alloy. In order to guarantee hermetic sealing, each device is resin-sealed.

The operating principle is based on the concept that the thermal pellet will melt in the event that the ambient temperature reaches a specific level. Consequently, the electrical current will be interrupted immediately in order to protect the appliance. All types of thermal cutoffs are constructed as one-shot operation devices. The thermal reaction is irreversible once it has occurred, and the thermal cutoff device must be replaced.

A wide choice of thermal cutoffs with broad ranges of operating temperatures and rated currents, as well as specific variations, is provided in order to perfectly suit the unique needs of each application. For more detailed information, please refer to our thermal cutoff product pages or our SEFUSE® Catalog on the download page.

Advantages of the Technology

Our thermal cutoff technology supporting our SEFUSE® products offers the following benefits:
  • Environmentally-friendly technology, several versions meet the Directive on Waste Electrical and Electronic Equipment Directive (WEEE), and the Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment (RoHS)
  • Remarkable sensitivity to abnormal temperatures due to the small size of the thermal cutoff devices
  • Resin-seal guarantees high reliability and accuracy
  • Some versions are able to operate under large currents (0.5A – 15A range)
  • Wide range of operating temperatures (73°C – 240°C)


The thermal cutoff technology supporting our SEFUSE® products is used in a multitude of appliances such as:
  • Irons, hair dryers and heaters
  • Refrigerators, rice cookers, hot water pots, coffee makers
  • Air conditioners, ventilation fans, electric fans, gas boilers
  • Transformers, power suppliers, adaptors, solenoids
  • Chargers, battery packs
  • Copiers, laser beam printers, power taps