Circuit Breaker 3P B-25A 10kA ETI — three-pole miniature circuit breaker, B curve, 25 A, 10 kA breaking capacity

Circuit Breaker 3P B-25A 10kA ETI is a three-pole miniature circuit breaker with a B tripping characteristic, rated for 25 A and a nominal breaking capacity of 10 kA. It is designed for protection of three-phase circuits against overloads and short circuits in residential and light-commercial distribution boards. The modular device is suitable for DIN-rail mounting and provides selective protection of each phase while allowing disconnection of all poles simultaneously.

Advantages

This ETI three-pole breaker combines a standard B curve sensitivity with a 25 A rated current, offering reliable protection for circuits with predominantly resistive or light inductive loads. The 10 kA breaking capacity covers common fault levels in household and small commercial installations. Its modular design and DIN-rail compatibility simplify installation and replacement in distribution panels.

Suitable for

• Protection of three-phase lighting and socket circuits in residential properties
• Light-commercial electrical panels and small workshops
• Distribution boards where simultaneous disconnection of all phases is required

When it may not be suitable

This breaker may not be appropriate for installations with higher prospective short-circuit currents than 10 kA; in such cases a device with higher breaking capacity is required. It is also not ideal for circuits requiring C- or D-curve characteristics where higher inrush currents from motors or transformers are present.

Key specifications

• Poles: 3 (three-pole)
• Tripping characteristic: B curve (suitable for resistive/low inductive loads)
• Rated current: 25 A
• Nominal breaking capacity: 10 kA
• Mounting: DIN-rail modular mounting for distribution boards
• Application: Protection against overloads and short circuits in three-phase circuits

How to use

Install the breaker on a standard DIN rail inside the distribution board, ensuring correct wiring of all three phase conductors and proper tightening of terminals according to the conductor size and torque recommendations. Use the device as the primary protective element for the designated three-phase circuit; in the event of overload or short circuit the breaker will trip and disconnect all poles. After fault clearance, reset the breaker manually by switching it back to the ON position.

What to consider before purchase

• Confirm that the installation’s prospective short-circuit current does not exceed 10 kA
• Verify that a B tripping curve is appropriate for the connected loads (not recommended for high inrush currents)
• Ensure the distribution board has space and a compatible DIN rail for a three-pole modular breaker

Usage recommendations

For reliable operation, match the breaker’s rated current and tripping characteristic to the circuit load profile, ensure proper terminal tightening and periodic inspection after any fault events; replace the device if signs of damage or wear are observed.