The Schneider Electric A9DR3720 is an Acti9 iCV40 XA combined RCBO — a single module that packs a 20 A C-curve MCB and a 30 mA residual-current device into a 3P+N, 4-pole package. The thermal-magnetic trip handles overloads and short-circuits; the integrated RCD covers the 30 mA sensitivity for personnel protection.
The 30 mA earth-leakage sensitivity is the standard for socket-outlet and personnel protection circuits.
The 3P+N unit occupies 10 modules at 9 mm pitch (90 mm total width). Neutral is on the left. Connection pitch is 18 mm between phases, 9 mm between phase and neutral. Wire stripping length is 14 mm for the bottom connection. IP20 body, IP40 inside the modular enclosure — fine for a dry indoor distribution board, not for washdown areas.