The Siemens 5SU9346-1CN20 is a 4-pole RCBO from the SENTRON series — an RCD-operated circuit breaker combining overcurrent and residual current protection in one 7-module-wide unit. It carries a 20 A rated current at 30 °C with a C tripping characteristic and a 30 mA residual current sensitivity, breaking capacity rated at 6 kA per EN 60898 and IEC 60947-2. The C curve means it handles moderate inrush from motor or lighting loads without nuisance tripping — typical for commercial and light industrial final circuits.
Ratings and derating
The 20 A rating holds at 30 °C ambient; at 40 °C it derates to 18.6 A, at 45 °C to 17.6 A, at 50 °C to 17.2 A, and at 55 °C to 16.6 A. If the panel runs warm — say a crowded enclosure near a drive cabinet — use the 40 °C figure for continuous load planning. The insulation voltage is rated at 440 V, overvoltage category III, pollution degree 2, which covers fixed-installation distribution boards.
Mounting and integration
Occupies 7 modular width units on a DIN rail. Depth is 77 mm, installation depth 70 mm, width 126 mm, height 90 mm. Supply can enter from top or bottom. Mounting position is any — no restriction for horizontal or vertical rail orientation. IP20 with conductors connected, so it lives inside a distribution board, not exposed to washdown. Touch protection is built in.