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A thermal switch is an electromechanical device which opens and closes contacts to control the flow of electrical current in response to temperature change.

The term “Thermal Cutoff Switch” generally refers to how the switch is used, ie. It cuts off the current to critical machinery when a temperature limit is exceeded preventing potential burn out or failure.  The applications of, and need for electromechanical thermal switch devices are broad and cover a huge diversity of industry applications. In their most basic form, they can be found on home appliances such as dryers for over temp protection.  Thermal cutoff switches are also used widely in industrial equipment.

Asiatronix is acting as European local office for Uchihashi, leader in thermal cutoff. Uchihashi thermal cutoffs ensures the safe and reliable operation of a wide range of products in which they are incorporated, providing optimal safety solutions.  

Accurate, reliable range of solutions to the need for upper limit temperature protection: 

  • thermal cutoffs - axial type from 0.3 to 11 A
  • thermal cutoffs - radial type from 0.8 to 3 A
  • Thermal cutoff/ Resistor Assemblies from 1 to 3 W
  • Thermoprotector with resistor (A5MC for example) working at 12 A rated current
  • Fusing Resistor (BZ05 for example) up to 120 A rated current





  • from 0.3 to 11A - AC (250V) and DC (50V)
  • different sizes: from 1,4 mm to 3,3 mm
  • specific series for Lithium Ion Rechargeable batteries, overheat protection of voltage dependent resistor, surge protection device, lighting surge protection


  • from 0.8 to 3A (AC 250V)
  • case length: from 4 to 11 m
  • series with ceramic case for higher thermal sensitivity 
  • specific series for: flow soldering, screw fixing


  • 10-15A (250V AC)
  • metal casing and sense temperature material of organic compound pellet
  • non-return type



  • High reliable inrush current device for switching mode power supplies 
  • Rated power: 1.0 -5.0W
  • Combination of thermal links of fusible alloy type  and wire wound resistor type




  • Current: 75A - 120A 
  • Up to 400V DC 
  • In higher current condition, these series accept high current and open the circuit quickly 


 Some series example below: 

  • High performance tco which combine two coil-winding resistors with a fusible alloy type thermal cutoff
  • It reduces the mounting space and decrease the number of components
  • It uses a coil-winding for greater ability to withstand inrush current
  • the marking printed on the topside make easier to confirm the products
  • Non-resettable thermal cutoff
  • Extremely simple construction ensures reliability, and hermetically sealed thermal element reduces deterioration with age
  • Superior thermal sensitivity
  • Insulating container
  • NC Series: suitable for reflow soldering
  • High performance thermal cutoff which combine a cement resistor with a fusible alloy type tco 
  • Overheat protect function
  • Superior characteristics against inrush current
  • Extremely robust electrical insulation and voltage withstanding properties after it functioned 


HIGH CURRENT TCO - BZ05 SERIESfuse_bz05_Series_Uchihashi_asiatronix

  • It can accept high current, 75A DC, and open a circuit quickly by receiving signal-current.
  • It can open a circuit quickly, within 60 sec. at room temperature by low signal current, below 1.5A
  • Resistor portion is connected to fuse portion electrically and it can cut off the both portions simultaneously.
  • It can be installed by fastening screw.
  • It is suitable for overcharge protect circuit of Lithium-Ion battery pack.
  • It does not contain lead (Pb) and cadmium (Cd) in compliance with RoHS.
  • It does not contain 46 substances of very high concern (SVHC) that are specified by REACH as of Dec. 2010.



You can find all the product range here 

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Uchihashi Estec is into the manufacturing of thermal cutoffs since 1918. Since then, the company has been pursuing advanced special alloy processing techniques and applied technologies. For nearly a century, the company has been spearheading the development of the most advanced alloy technologies – including the successful commercialization of the world’s first small alloy thermal cutoffs – while helping improve product safety and reliability in the manufacturing industry.