Residual current devices for mounting on circuit breakers

The RCD310, RCD510, RCD320, RCD520 and RCD820 residual current devices are available as accessories for mounting on specific 3VA molded case circuit breakers up to the largest circuit breaker size/current rating.

Combination with circuit breakers

After a residual current device has been mounted on a molded case circuit breaker or switch disconnector, the specifications of the breaker or disconnector remain unchanged with respect to the following characteristics:

  • Standards

  • Conductor cross-sections

  • Use of connection accessories

  • Isolating features

  • Selective behavior

When a basic type residual current device is mounted on a 3VA1 molded case circuit breaker or a 3VA1 switch disconnector, the electrical rating of the equipment combination is automatically downgraded to the lower electrical rating of the residual current device.




≤ 690 V AC

3VA1 and Basic residual current device

≤ 480 V AC

For more information, refer to chapter Technical specifications.

Residual current devices


The combination of molded case circuit breaker and residual current device conforms to IEC 60947‑2 Annex B.

Power supply

The residual current devices do not require an external power supply, but tap a supply from the main current paths of the molded case circuit breaker or switch disconnector.

Guaranteed to function properly

Proper functioning of the residual current device is guaranteed even with only one phase and N (applies to RCD320, RCD520 and RCD820) or two phases (alternating current or pulsating direct voltage).

Direction of incoming supply

The direction of incoming supply to the combination of circuit breaker and residual current device is optional, i.e. it can be connected at the top or bottom. The performance of the residual current devices is not impaired by regenerative feedback from motors.

Device type

All residual current devices meet the requirements for device type A, i.e. they are capable of detecting all sinusoidal AC residual currents and pulsating DC residual currents.

Combination with external accessories

DIN rail adapters

DIN rail adapters are available as accessories for side-mounted residual current devices RCD310 and RCD510 up to 160 A. These permit fast and easy installation of residual current devices on 35 mm DIN rails compliant with IEC / EN60715 TH35‑7.5 and TH35‑15.

For further information, please refer to chapter DIN rail adapter.