Manual Trip - ON/OFF Switches
Many models are available with a manual trip feature, either standard or as an option.
Others are specifically designed as combined switch/circuit breakers
with rocker, push button, or toggle actuation, styled for front panel mounting. Rocker types are available with illumination as an option.
According to IEC 934/EN 60934:
- R = manual reset only
- M = with manual release but not intended for frequent use as a switch
- S = combined switch/CBE function
- J = automatic reset
Trip Free Mechanism
E-T-A circuit breakers cannot be held closed against an overload. This is achieved through the use of positively trip free designs in accordance with IEC 934/EN 60934 (with the exception of models 1410, 1610, 1658 and 808 which are designed for specialised applications).
The snap-action mechanism featured in many E-T-A models ensures that the contact closing speed is independent of the speed of operation of the actuator (push button, rocker, toggle etc.). The moving contact is retained until the actuator causes a defined force to act in the closing direction of the contacts. Once this force is exceeded, the mechanical retention is overcome allowing the contacts to snap closed (tease free mechanism.) The closing speed is a function of this force alone.
Snap-action mechanisms eliminate contact welding upon switching on to sustained short-circuits and minimise the risk of contact wear over the circuit breakers' life.