RCD-operated circuit breaker — 20 A, Type A, C-curve
The Siemens SENTRON 5SU9356-7KN20 is an RCBO — a combined RCD and MCB in one 2-module (36 mm wide) package. The Type A RCD detects pulsating DC fault currents as well as sinusoidal AC, which covers variable-speed drives and electronic loads. Rated current derates with ambient temperature: 18.8 A at 40 °C, 18.2 A at 45 °C, 17.4 A at 50 °C, and 16.2 A at 55 °C. If the panel runs hot, size the load accordingly.
Mounts on DIN rail, any position. Supply can enter from top or bottom; the RCBO is polarity-sensitive on the 1P+N configuration (switched phase, solid neutral).