On TD125U to TS800U circuit breakers, the thermal-magnetic is built in trip units. Some models of the TD&TS series circuit breakers are UL Listed to be applied at up to 100% of their current rating. Because of the additional heat generated, the use of specially designed enclosures and 90°C rated wire and the wire size are required when applying circuit breakers at 100% of continuous current rating.
Protection of power distribution - Overload protection: Thermal protection with a fixed or adjustable threshold - Short-circuit protection: Magnetic protection with a fixed or adjustable pick-up
Thermal magnetic types - Time-Delay operation An overcurrent heats and warps the bimetal to actuate the trip bar by the bimetal characteristic. - Instantaneous operation If the overcurrent is excessive, the armature is attracted and the trip bar actuated by electromagnetic force.