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Thermal Protector C08

Power class: 4,0 A to 25,0 A
Type series: 08

  • normally open
  • resets automatically
  • with connector cables
  • without insulation
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Thermal Protector C08
Thermal Protector C08
Thermal Protector C08
Thermal Protector C08

Switchgear consisting of a mobile and circular contact bridge (1), a contact bearing pin (2), a spring snap-in disc (3) and a bimetallic disc (4) which is riveted into one another, undetachable and fixed in a positive lock and self-aligning between a non-conductive floor of a housing (5) and an insulating ceramic bearing (6) with two integrated stationary contacts (7) as electrodes. At the same time, the switchgear is initially held open by the spring snap-in disc (3) with the contact bridge (1) acting as a transfer element for electric current after the switching process) which is fastened between a supporting collar and a circumferential ring. As such, the bimetallic disc (4) underlying it, that is also stuck out from the contact bearing pin (2), can continuously work (exposed) by mechanical loads without the distance between the contact surfaces (defined by the spring snap-in disc (3)) diminishing. As soon as the bimetallic disc (4) reaches its rated switching temperature, it effectively springs against the throw force of the spring snap-in disc (3) into its inverted position. The contacts (7) are abruptly closed. The temperature will now fall. The bimetallic disc (4) will only snap back upon reaching a defined spring back temperature and the contacts will be abruptly opened again. As a result of the dimensioning of the contact bearing pin (2), an easy, circular rotation of the circle-shaped contact bridge (1) is enabled with every switch so that transfer resistances remain constantly below the minimum limit after many switch cycles and the long term stability is sustained even under high levels of stress.

Technical specifications

Nominal switching temperature (NST) in 5°C
70 °C - 180 °C
Tolerance (standard)
±5 K
Reverse switch temperature (RST)
≥ 35° C (≤ 95° C NST)
-50 K ± 15 K (≥ 100° C ≤ 180° C NST)
≥ 35 °C
(defined reset temperature possible on customer request)
Installation height from
6.6 mm
9.0 mm
Resistance to impregnation
Suitable for installation in protection class
Pressure resistance to the switch housing
600 N
Standard connection
Lead wire 0.75 mm² / AWG18
Operating voltage range AC
up until 500 V AC
Rated voltage AC
250 V (VDE) 277 V (UL)
Rated current AC cos ϕ = 1.0 / cycles
10.0 A / 10,000
Rated current AC cos ϕ = 0.6 / cycles
6.3 A / 10,000
Total bounce time
< 1 ms
Contact resistance (according to MIL-STD. R5757)
≤ 50 mΩ
Vibration resistance at 10 ... 60 Hz
100 m/s²


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