Thermal-Magnetic Overcurrent Circuit Breakers

Typical Applications

Ideally suited to protect against overcurrent and short circuit of equipment in telecommunications, process control and other industrial applications where sophisticated equipment requires a high precision performance.


A latching type bimetal is combined with a magnetic coil to ensure protection and genuine physical contact isolation. This provides the joint benefits of delayed operation for low level overcurrent protection and fast magnetic action of higher value short circuits, disconnecting the faulty circuit within milliseconds.


Thermal-magnetic circuit breaker for rail
mounting, low resistance option


Thermal-magnetic circuit breaker, socket
or panel mounting, single or multipole


Thermal-magnetic circuit breaker
for rail mounting, single or multipole


Thermal-magnetic circuit breaker, small width,
pcb or threadneck panel mounting


Thermal-magnetic circuit breaker,
small width, threadneck mounting


Thermal-magnetic circuit breaker,
small width, with slide actuator, plug-in mounting


Thermal-magnetic circuit breaker, snap-in mounting, 1-, 2-pole

3300 fast acting
3400 standard delay

Thermal-magnetic circuit breaker with auxiliary contact option, threadneck mounting


Thermal-magnetic circuit breaker with
manual release facility, flange mounting

3600 standard version
3900 low-resistance version

Thermal-magnetic circuit breaker with auxiliary contacts, socket mounting


Single pole and multipole thermal-magnetic miniature circuit breakers (MCBs) in accordance with EN 60947-2, UL 1077 and UL 489


Differences and Similarities Between K Curve and D Curve Breakers

A Miniature Circuit Breaker (MCB) is a resettable protective device that prevents electrical circuits from catching fire and causing damage to personnel and property. It is a device designed to isolate a circuit during an overcurrent event without using a fusible element. There are two types of overcurrent events; a thermal overload and a short circuit.

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