It adds earth-leakage protection to a 3P+N circuit rated at 40 A and 400 V AC, with a 30 mA sensitivity and Type A-SI (Super Immunised) waveform discrimination. The 4-module (9 mm pitch each) body mounts on DIN rail via the clip-on mechanism, so it integrates into a standard distribution board or sub-panel as a combined RCBO assembly when paired with the matching MCB.
The 40 A rated current (In) sets the continuous load the RCD can carry without derating; it matches a 40 A MCB in the same Acti9 range, so the pair forms a coordinated RCBO. The instantaneous time delay (no intentional delay) ensures the RCD clears the fault within the standard 40 ms window, which is critical for coordination with upstream selective RCDs — the instantaneous unit trips first, leaving the upstream time-delayed device to act as backup.
Clip-on mounting on DIN rail — no tools needed for the rail attachment. The neutral position is left, so verify the orientation matches the busbar and the adjacent MCB's neutral take-off point. Bottom tunnel terminals accept 1…16 mm² rigid or 1…10 mm² flexible cable; tighten to 2 N·m. Strip length is 14 mm for the bottom connection. The electrical connection to the MCB is by screws, so the RCD is mechanically and electrically linked to the line-side breaker. IP20 on the body (finger-safe), IP40 inside a modular enclosure — standard for distribution boards.