What this RCBO is and what the ratings mean for fit
The Siemens 5SU9353-1KK32 is a 2-pole RCBO — an RCD-operated circuit breaker that combines overcurrent protection and residual current detection in one 36 mm-wide module. It's a SENTRON-series instantaneous type, rated 32 A at 30 °C with a C tripping curve, meaning it handles moderate inrush from motor or lighting loads without nuisance trips while still clearing faults fast. The 30 mA residual-current rating is the standard for personal protection against electric shock in commercial and industrial final circuits. Breaking capacity is 4.5 kA per EN 60898, which covers most sub-distribution boards fed by a transformer or upstream breaker with a higher interrupting rating.
Mounting and panel integration
Snaps onto DIN rail, 2 modular width units (36 mm), 77 mm deep. Mounting position is any orientation, and the supply can enter from top or bottom — no forced orientation on the panel layout. Installation depth is 70 mm, so it fits standard 80 mm-deep enclosures with a bit of wiring room behind. Touch protection is built in, and IP20 applies once the distribution board cover is on and conductors are connected.