2CDS273061R0505 ABB S203M-B50UC MCB 10 kA 3P Type B 50 A

Why Choose the ABB S203M-B50UC Miniature Circuit Breaker?

The ABB S203M-B50UC is a high-performance three-pole universal-current miniature circuit breaker (MCB) designed for reliable overload and short-circuit protection in AC and DC electrical systems. As part of the ABB System pro M compact® S200 M UC series, it combines a 50 A rated current, Type B tripping characteristic and 10 kA short-circuit breaking capacity for demanding industrial, distribution, control and railway applications.

Designed for universal-current applications, the S203M-B50UC uses thermal-magnetic operation to protect conductors and connected equipment against sustained overloads and short circuits. Its Type B characteristic provides a relatively sensitive magnetic response for circuits with low normal starting and inrush currents, making it suitable for resistive loads, distribution circuits and other applications requiring dependable fault protection.

With a rated current of 50 A, three poles and a 10 kA short-circuit breaking capacity, the S203M-B50UC provides robust protection for higher-current multi-pole circuits. Its 400 V AC / 400 V DC rating and compact DIN-rail construction support straightforward integration into distribution boards, switchgear assemblies and industrial or railway electrical systems.

Key Advantages

• Versatile miniature circuit breaker for AC and DC applications.
• 50 A rated current for higher-current distribution and equipment circuits.
• Three-pole configuration for multi-pole circuit protection.
• Type B tripping characteristic suited to circuits with relatively low starting and inrush currents.
• 10 kA short-circuit breaking capacity for robust fault protection.
• 400 V AC / 400 V DC rated voltage for universal-current applications.
• Part of the ABB System pro M compact® platform for flexible system integration.

Key Features

• ABB S200 M UC universal-current MCB series.
• 50 A rated current.
• 3-pole configuration.
• Type B tripping characteristic.
• 10 kA short-circuit breaking capacity.
• Rated for 400 V AC and 400 V DC.
• Thermal-magnetic overload and short-circuit protection.
• IP20 protection rating.
• 20,000-cycle electrical endurance.
• -25 °C to +55 °C operating temperature range.
• Compact DIN-rail construction.
• Suitable for industrial and railway applications.

Reliable Protection for AC and DC Circuits

Miniature circuit breakers such as the ABB S203M-B50UC protect electrical conductors and connected equipment against excessive current caused by overloads and short circuits. The thermal release responds to sustained overload conditions, while the magnetic release provides rapid interruption when fault current reaches the breaker’s instantaneous tripping threshold.

The Type B characteristic makes the S203M-B50UC suitable for circuits where normal operating loads have relatively low starting or inrush currents. Combined with the universal-current capabilities of the ABB S200 M UC series, this provides flexible protection for AC and DC distribution systems, industrial equipment, auxiliary circuits and railway electrical installations.

Typical Applications

• Industrial AC and DC distribution systems.
• DC auxiliary and power distribution circuits.
• Railway electrical systems.
• Resistive loads with relatively low inrush currents.
• Industrial control and automation panels.
• Electrical distribution boards and switchgear assemblies.