The Siemens SENTRON 5SU1323-1WM16 is a 2-pole RCBO (residual current circuit breaker with overcurrent protection) combining a 16 A rated current, 30 mA residual current sensitivity, and a C tripping characteristic in one 4-module-width package. It's a Type AC device — meaning it detects sinusoidal AC fault currents — and carries a 4.5 kA breaking capacity under EN 60898 and 15 kA under IEC 60947-2, so it can handle fault levels typical of residential and light commercial distribution boards.
The IP20 rating applies once the distribution board is installed with connected conductors — it's not a standalone outdoor device. Terminals accept 1.5 mm² to 25 mm² conductors, which covers most branch-circuit wiring from lighting circuits to small motor feeds. Neutral conductor switching is built in, and the supply can land on either the top or bottom terminals.
Compared to the 5SU9304-1KK32 (a 1P+N RCBO at 32 A, 10 kA EN 60898), this 5SU1323-1WM16 is a true 2-pole device with neutral protection on both poles, a higher IEC 60947-2 rating (15 kA vs 10 kA), and a wider conductor range up to 25 mm². The 5SU9304-1KK32 is narrower at 1 width unit but lacks the second protected pole and the higher fault-current rating. If the panel design calls for a 2-pole protected neutral and 15 kA IEC capacity, the 5SU1323-1WM16 is the correct fit — the 5SU9304-1KK32 won't drop in without rewiring and a rating review.