Residual current circuit breaker 4P 40A 0.3A Type AC Legrand P304 (model 411728)

Legrand residual current circuit breaker P304 (4P, 40 A, 0.3 A sensitivity, Type AC) is intended to detect alternating-current earth-leakage faults and interrupt supply to reduce risk to people and equipment. The device is designed for installation in distribution boards where AC-only residual current protection is required, providing coordinated disconnection of all four poles for TN, TT and IT system arrangements where AC leakage detection is appropriate.

Advantages

The four-pole configuration ensures simultaneous isolation of all live conductors and neutral, supporting safe maintenance and fault clearing. The 40 A rated current matches common branch and small main circuits while the 0.3 A (300 mA) trip sensitivity gives reliable earth-fault detection for protection against fire and major leakage currents. Type AC detection focuses on alternating sinusoidal leakage currents, ensuring accurate tripping for typical AC fault conditions. The compact form factor and mounting compatibility make it suitable for standard DIN rail distribution panels.

Suitable for

• Residential and apartment building distribution boards requiring four-pole AC-only RCCB protection
• Commercial small-to-medium installations with balanced three-phase loads and neutral
• Light industrial environments where AC leakage detection at 300 mA sensitivity is required

Key specifications

• Poles: 4-pole (simultaneous disconnection of all phases and neutral)
• Rated current: 40 A
• Residual operating current (trip sensitivity): 0.3 A (300 mA)
• Type: AC (responds to AC sinusoidal residual currents)
• Mounting: DIN-rail compatible enclosure for standard distribution panels
• Application: Fixed installation for earth-leakage protection of circuits

How to use

Install the RCCB in a suitable distribution board on a standard DIN rail and connect the incoming supply conductors to the line side and outgoing circuit conductors to the load side following the manufacturer’s wiring diagram. Ensure the four poles are connected to the corresponding phases and neutral conductor. Verify the device is accessible for testing and tripping. After wiring, perform an insulation and continuity check of the installation and operate the test button, if provided, to confirm correct trip operation before energizing the protected circuits.

Usage recommendations

Use this Type AC RCCB where detection of alternating residual currents is sufficient; it is not intended for detecting pulsating DC or filtered faults (select Type A or Type B devices for those applications). Ensure the rated residual current of 300 mA matches the protection objective (fire and major leakage protection rather than personal protection at lower sensitivities). Regularly test the device according to local regulations and manufacturer guidance to confirm reliable operation.