Residual Current Relay Hager CD441J 30 mA 4×40 A AC

Hager CD441J 30 mA 4×40 A AC is a residual current relay designed to detect and interrupt dangerous earth leakage in AC circuits. The device is configured as a four-pole relay with four separate 40 A outputs, providing centralised residual-current protection for multiple outgoing circuits. With 30 mA sensitivity, it is intended to reduce the risk of electric shock and contribute to overall installation safety in residential and light commercial environments.

Advantages

The relay offers selective leakage detection with a rated residual operating current of 30 mA and four 40 A switching outputs for distributing protection across several circuits. Its compact design allows installation within distribution boards, and the AC-type sensitivity enables reliable detection of alternating residual currents. The device supports quick disconnection of supply in the event of dangerous leakage, helping to minimise the potential for injury and fire caused by earth faults.

Suitable for

• Residential electrical distribution boards
• Light commercial premises and small offices
• Protecting multiple outgoing circuits from earth leakage
• Upgrades or retrofits where central residual-current detection is required

Key specifications

• Type of protection: AC residual current detection
• Rated residual operating current: 30 mA
• Configuration: 4-pole relay
• Switching capacity per pole: 40 A
• Intended application: Leak detection and disconnection for safety

How to use

Install the residual current relay inside the distribution board according to local electrical regulations and wiring practices. Connect the supply and the four outgoing circuits to the corresponding input and output terminals, ensuring proper phase and neutral continuity. Verify correct operation by performing a functional test after wiring and after any maintenance; testing equipment or the built-in test facility (if present) may be used to simulate a residual current and confirm timely disconnection at 30 mA.

Recommendations

Follow national wiring standards and the manufacturer's installation guidelines. Ensure that protective coordination with upstream and downstream devices is observed so that nuisance trips are minimised while maintaining required safety levels. Perform periodic functional testing and visual inspection to confirm continued reliability.