Mini Circuit Breaker ABB SH203-B 3P B 25A 6kA (MPN 2CDS213001R0255)

ABB SH203-B 3P B 25A is a three-pole mini circuit breaker designed for overload and short-circuit protection in low-voltage distribution installations. With a B-curve tripping characteristic and a rated current of 25 A per pole, this device provides selective protection for circuits with predominantly resistive loads such as lighting and domestic sockets. Its breaking capacity of 6 kA ensures reliable interruption of fault currents in residential, commercial and light industrial distribution boards.

Advantages

The breaker combines a compact three-pole design with stable thermal-magnetic tripping, offering reliable protection against overloads and short circuits. The B curve provides fast response to moderate short-circuits while maintaining tolerance for temporary inrush currents from appliances. The device is suitable for DIN-rail mounting and integrates with standard low-voltage distribution systems, allowing straightforward installation and replacement.

Suitable for

• Protection of three-phase lighting circuits in residential and commercial buildings
• Protection of small motor circuits and socket groups with predominantly resistive or low-inrush loads
• Use in distribution boards where coordinated selective protection and compact three-pole devices are required

When it may not be suitable

This B-curve breaker may not be appropriate for circuits with high motor starting currents or heavy inductive loads that require a delayed or higher inrush tolerance, where a C- or D-curve device would be more suitable. It is also not intended for applications that demand breaking capacities above 6 kA or for use as a main switch in installations requiring higher fault-level ratings.

Key specifications

• Poles: 3 (three-pole)
• Tripping curve: B (thermal-magnetic)
• Rated current: 25 A per pole
• Rated breaking capacity: 6 kA
• Mounting: DIN-rail compatible for low-voltage distribution boards
• Application: overload and short-circuit protection in low-voltage circuits

How to use

Install the breaker on a standard DIN rail inside the distribution board according to local electrical codes. Connect the incoming supply and outgoing load conductors to the appropriate terminals for the three phases, ensuring proper tightening torques and polarity. After installation, verify correct operation by switching the device on and off and, if required, perform insulation and continuity tests on the protected circuits before energising. Use coordinated protection settings and upstream devices as needed to ensure selectivity.

What to consider before purchase

• Match the tripping curve and rated current to the protected load characteristics (B-curve is for resistive/low-inrush loads)
• Verify that a 6 kA breaking capacity is sufficient for the prospective fault level of the installation
• Confirm mechanical compatibility with the distribution board and DIN-rail mounting space

Usage recommendations

For circuits with lighting, domestic sockets and small appliances, use this three-pole B-curve breaker for reliable overcurrent protection. For motor loads or high inrush equipment, consider selecting a breaker with a C- or D-curve and/or higher breaking capacity to ensure correct coordination and reduce nuisance trips.