Residual-current device Schneider Electric A9Z21425, Type A, 25 A, 380–415 V, 1500 A breaking capacity

Schneider Electric A9Z21425 is a four-pole residual-current device (Type A) designed to detect AC and pulsating DC earth leakage currents in low-voltage installations with a nominal voltage range of 380–415 V. With a rated current of 25 A and a breaking capacity of 1500 A, this compact DIN-rail mounted unit provides selective protection for circuits in residential and commercial distribution boards. The device fits standard panel installations and is intended for use where detection of both alternating and pulsating direct leakage currents is required.

Advantages

The device offers reliable earth-fault detection for AC and pulsating DC residual currents, combining accurate sensitivity with a compact footprint for space-constrained panels. Its four-pole design ensures simultaneous disconnection of all phases and neutral where applicable, improving safety in three-phase systems. The 1500 A breaking capacity provides robustness for typical overload and short-circuit conditions in consumer and light-commercial installations.

Suitable for

• Protection of three-phase distribution circuits in residential and commercial switchboards
• Electrical panels that require detection of AC and pulsating DC leakage currents
• Applications with nominal system voltages of 380–415 V

Key specifications

• Device type: Type A residual-current device (RCD)
• Poles: 4P (four-pole)
• Rated current: 25 A
• Rated operational voltage: 380–415 V
• Residual operating current: 30 mA
• Breaking capacity (Icn): 1500 A
• Mounting: DIN-rail
• Dimensions (approx.): 72 × 73 × 91 mm

How to use

Install the residual-current device on a standard DIN rail inside the distribution board following local wiring regulations and the manufacturer's installation instructions. Connect the supply and load conductors to the corresponding terminals, ensuring correct phase sequence and secure terminations. Verify the device is compatible with the upstream overcurrent protection and system earthing arrangements. After installation, use the test button to confirm correct operation and trip response before placing the circuit into service.

Recommendations

Regularly test the device using the built-in test button at intervals recommended by local regulations to ensure continued sensitivity to earth leakage. Ensure coordination with upstream protective devices and verify that the selected rated current and residual operating current suit the protected circuits and applicable safety standards.