Its 40 A rating at 30 °C and C-curve tripping characteristic suit it for motor and lighting loads with moderate inrush — think pump starters, compressor contactors, or fluorescent banks where the magnetic trip needs to ride through a short startup surge without nuisance opening. The 2-module width (36 mm) and 77 mm depth fit standard DIN-rail enclosures; supply can enter from either top or bottom, which simplifies busbar routing in a crowded panel. IP20 applies once the distribution board is installed with conductors connected — this is a protected-enclosure device, not a standalone outdoor unit.
Two breaking-capacity ratings are on record: 4.5 kA per EN 60898 and 10 kA per IEC 60947-2. The 10 kA rating gives headroom for selectivity with an upstream MCCB or fuse — important when coordinating a downstream sub-distribution board.
Derating and ambient temperature
The manufacturer provides a full derating curve: 37.6 A at 40 °C, 36.4 A at 45 °C, 34.8 A at 50 °C, 32.4 A at 55 °C and 60 °C, 30.8 A at 65 °C, and 29.2 A at 70 °C. In a sealed panel with multiple RCBOs ganged together, the effective current must be reduced per these values — a common oversight that leads to nuisance tripping in summer conditions.