Residual-current circuit breaker 4P 40A 30mA Type AC Legrand P304 (MPN 411708)

Legrand P304 residual-current circuit breaker 4P 40A 30mA Type AC is designed to detect alternating residual currents and cut off supply to reduce the risk of electric shock and fire. This four-pole RCCB is intended for three-phase installations and distribution boards where protection against earth leakage is required. The device combines a compact form factor with clear switching operation and is suitable for integration into industrial and commercial electrical panels.

Advantages

The RCCB provides reliable detection of AC-type leakage currents with a rated residual operating current of 30 mA and a rated current of 40 A, ensuring fast disconnection in fault conditions. Its four-pole design enables neutral and all three phases to be monitored and disconnected simultaneously. The switch mechanism is designed for visible on/off position and straightforward manual operation. The product is manufactured by a recognised electrical systems supplier, ensuring compatibility with standard mounting and wiring practices.

Suitable for

• Three-phase residential and commercial distribution boards
• Industrial electrical panels requiring earth-fault protection
• Protection of circuits feeding motors, lighting and general loads
• Applications where AC-only leakage detection is sufficient

Key specifications

• Poles: 4 (three phases plus neutral)
• Rated current: 40 A
• Residual operating current (sensitivity): 30 mA
• Type: AC (detects alternating leakage currents)
• Function: residual-current detection and manual switching/disconnection
• Mounting: standard DIN-rail compatible form factor for distribution boards

How to use

Install the RCCB in the distribution board following local electrical codes and safety practices. Connect the three phase conductors and neutral to the corresponding terminals, and ensure secure tightened connections. The device should be placed upstream of the circuits it protects so that leakage currents are detected and the supply is disconnected when a residual current exceeds 30 mA. After installation, test the device using appropriate testing procedures or a test button if available and verify correct operation before energising the downstream circuits.

Usage recommendations

Regularly verify functionality by performing periodic tests according to local regulations and maintenance schedules. Use the RCCB in systems where AC-type leakage detection meets protection requirements; for installations with DC components or high-frequency residuals, consider devices with appropriate sensitivity types. Ensure the breaker’s rated current matches the protected circuit and coordinate with upstream and downstream protective devices.