4pole MCCB for 4 wire connections, with an additional 4th pole for neutral wire connection, so that power can be supplied between neutral and any of the other three. In 4-Pole MCCBs, the neutral pole, like the phase poles, has a protective release. Application Three-phase power supply with a neutral. Miniature circuit breakers (MCBs) safely cut the connected circuit in the event of an overload or a short-circuit, protecting electrical systems and devices from damage. The devices have a consistent design and can be expanded to include many more functions with the help of a wide range of accessories. Our extensive portfolio has the right MCB for every application, whether it's for industries, buildings, or infrastructure.