SETsafe | SETfuse Offers Innovative, Optimal Thermal Protection

 December 20th, 2023 |   By Area51 Electronics  |   0 Comments

SETsafe | SETfuse – a leading manufacturer of circuit protection solutions and components – is known for their innovative solutions for high standard safety and protection. One of their best-seller products is the TFMOV-M Thermally Protected Varistors featuring two series – TFMOV10M and TFMOV20M.

What Is Thermal Protection MOV?

MOV stands for metal oxide varistor and is an electrical component designed to suppress the surge voltage and protect the subsequent circuit. MOV can suppress transient overvoltage, but it’s also prone to degradation failure. So, when a varistor degrades or fails, there is an increased risk of burning. In the event of a voltage spike or surge, a thermal protection varistor TFMOV-M can be used as the surge protection element, and to improve the safety of the circuit.

TFMOV-M is a combination of varistors (MOV) and thermal protection design, enclosed in a protective casing. When the temperature of the MOV is abnormally exceeded, the thermal protection design will take action and the isolated part will cut the arc of DC application completely, so that the failure mode of the MOV appears to be open-circuit failure. This is known as mechanical tripping.

Since the varistor has the characteristics of aging or degrading, the TFMOV-M provides powerful circuit protection by separating the varistor from the main circuitry by the thermal protection design when the varistor (MOV) degrades or fails.

The TFMOV-M is often used in things which require high reliability and weather withstanding, such as photovoltaic inverters, communication equipment, and power supplies in data centers, etc.


  • Thermal protection, high reliability
  • Remote signal contact for failure indication
  • Nanosecond response time
  • V0 flame retardant housing
  • Nominal discharge current (8/20 µs)(/n): 10kA, 20kA, 25 kA optional
  • Maximum discharge current (8/20 µs)(lmax): 25kA, 40kA, 50 kA optional
  • Mechanical tripping, fast response
  • Reliable function
  • Available in different sizes for more options
  • No arc fault risk


  • Commercial string inverter system
  • Home micro inverter system
  • Energy storage
  • Uninterruptable Power Supply (UPS)
  • Telecommunications equipment 
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