3-pole power circuit breaker 100A BG1 NZMB1-A100 259079

Protection of high-current 3-phase circuits

This device is a key component in distribution systems where precise protection against overloads and short circuits is required for rated currents up to 100 A. As a power circuit breaker from the NZM series, this model combines the functions of a disconnector and a thermal-magnetic protection unit, eliminating the need for additional components in the main circuit. Thanks to adjustable overload release settings in the range of 80 to 100 A, the installer can tailor the operating characteristics to the specific requirements of the protected load, such as an electric motor or transformer. Notably, the device maintains full electrical performance even at ambient temperatures up to 50°C, which is crucial when installed in compact industrial distribution boards.

Mounting flexibility and connection safety

The device construction is designed for convenient handling during both installation and subsequent operation. Main circuit terminals are located at the front of the enclosure, facilitating cable connection and reducing the risk of wiring errors. The use of frame-type terminals ensures secure and durable connections for conductors sized according to the rated current. Although the device is intended for fixed mounting, it can optionally be mounted on a DIN rail using dedicated accessories, increasing its versatility for various types of control cabinets.

Connection safety is confirmed by a high short-circuit breaking capacity – the device guarantees safe circuit interruption even at short-circuit currents of up to 25 kA at 400 V. This is a critical parameter for industrial installations, where sudden short circuits can generate enormous electrodynamic forces. The IP20 degree of protection ensures protection against solid objects with a diameter greater than 12 mm (e.g., fingers), but requires installation within enclosed distribution boards or control cabinets.

Key features and practical application

The instantaneous short-circuit release can be set in the range of 600 to 1000 A, enabling rapid power disconnection in the event of severe short circuits, minimizing damage to cables and downstream equipment. The absence of a built-in motor drive and auxiliary contacts in the standard version means this is a basic solution that can be expanded with additional modules (e.g., remote drives or auxiliary contacts) according to individual project requirements. Power losses of approximately 22 W indicate the device's energy efficiency during continuous operation at rated load.

The device is ideally suited as a main input protection in industrial distribution boards, protection for medium-power motors, and protection of supply lines in commercial and infrastructure facilities. Its compact design allows for efficient use of space within the distribution cabinet, while the modular concept of the NZM series enables easy functional expansion in the future without replacing the entire device. In practice, this means a three-pole construction adapted for a working voltage of 440 V, where each pole is equipped with its own tripping mechanism, and total energy consumption remains low thanks to an optimized current flow path.