What it is and what it does
The Siemens 5SU9346-1CN63 is a SENTRON RCBO — a combined RCD and MCB in one 4-pole unit, rated 63 A with a 30 mA residual-current trip of Type AC (sinusoidal AC fault currents only). The C-curve tripping characteristic means it handles inrush from motor or transformer loads up to 10× rated current before the magnetic trip fires, so it's a common choice for general-purpose distribution circuits feeding mixed inductive and resistive loads. Breaking capacity is 6 kA per both EN 60898 and IEC 60947-2, adequate for most residential and light commercial panelboards where the prospective fault current stays under that threshold.
Mounting and integration
Occupies 7 modular width units on a DIN rail — 126 mm wide, 77 mm deep, 90 mm tall. Installation depth is 70 mm. Rated IP20 once installed in a distribution board with conductors connected — standard for enclosed panel use, not for wet or dusty environments.
Thermal derating and environment
Full 63 A rating holds at 30 °C ambient. Derate to 58.6 A at 40 °C, 56.1 A at 45 °C, 54.8 A at 50 °C, and 53.6 A at 55 °C. If your panel runs warm, size the upstream protection accordingly. Operating range spans -40 °C to 75 °C. Halogen-free and silicon-free construction — relevant for environments sensitive to outgassing (clean rooms, food processing).