Eaton FRCMM-125/4/03-S/A Residual Current Circuit Breaker 4P 125A 300mA Type S/A

The Eaton FRCMM-125/4/03-S/A is a high-performance 4-pole residual current circuit breaker (RCCB) engineered to provide robust electrical protection in demanding industrial and commercial environments. This device is specifically designed to detect leakage currents and disconnect the circuit to prevent equipment damage and ensure personnel safety. As a Type S/A device, it offers selective operation, allowing for coordinated protection schemes where multiple breakers are installed in series.

Advantages

This residual current circuit breaker stands out due to its high current rating of 125A, making it suitable for heavy-duty electrical distribution systems. The Type S/A classification ensures that the device is sensitive to both alternating and pulsating direct fault currents, providing comprehensive protection. Its selective design is a significant advantage for complex installations, as it prevents nuisance tripping and ensures that only the faulty circuit is isolated, maintaining power continuity in the rest of the system.

Suitable for

• Industrial electrical distribution boards
• Commercial building power systems
• Selective protection in multi-stage electrical installations
• Protection against leakage currents in high-load circuits

When it may not be suitable

This device is not intended for residential applications where a lower sensitivity of 30mA is required for direct contact protection. It is also not suitable for circuits requiring instantaneous tripping, as its selective nature introduces a deliberate time delay.

Key specifications

• Number of poles: 4
• Rated current: 125A
• Rated residual current: 300mA
• Type: S/A (Selective, sensitive to AC and pulsating DC)
• Mounting: DIN rail

How to use

The Eaton FRCMM-125/4/03-S/A should be installed by a qualified electrician in accordance with local electrical regulations. It is designed for mounting on a standard DIN rail within a distribution cabinet. Ensure that the supply cables are correctly connected to the input terminals and that the load is connected to the output terminals, observing the correct phase sequence for 4-pole operation. After installation, perform a functional test using the integrated test button to verify the tripping mechanism.

What to consider before purchase

• Verify that the 300mA sensitivity meets your specific safety requirements.
• Ensure the 125A rated current is compatible with your main circuit load.
• Confirm that the selective (S) characteristic is appropriate for your system's coordination needs.
• Check the available space in your distribution board for a 4-pole device.

Usage recommendations: Regularly test the device using the built-in test button at least every six months to ensure the mechanical tripping mechanism remains functional and reliable over time.