The Siemens 5SU9356-8CN16 is a 1+N RCBO (residual current circuit breaker with overcurrent protection) rated 16 A, 6 kA breaking capacity, D characteristic, type A. It belongs to the Construction line — a range built for commercial and light-industrial final distribution boards where space is tight and the spec must be met without over-engineering. The D characteristic means it tolerates the inrush of motor-driven loads (pumps, small conveyors, lifts) without nuisance tripping, while the type A residual-current element detects pulsating DC fault currents that a basic AC type would miss — essential on circuits feeding single-phase rectified loads like switching power supplies or VFDs.
What the ratings mean for fit
The 6 kA breaking capacity is the short-circuit withstand at the device's terminals — adequate for most final sub-circuits downstream of a distribution board with a higher-rated upstream breaker. In a panel with a transformer-fed supply or a high-fault utility connection, verify the prospective short-circuit current at the point of installation does not exceed 6 kA. The 1+N pole configuration switches the phase and switches the neutral, but does not break the neutral on overcurrent — it opens the neutral only on residual fault. That is standard for single-phase RCBOs in many markets, but if your local code requires full neutral isolation on overcurrent, confirm before wiring.
Panel integration note
The RCBO snaps onto standard DIN rail (EN 60715) inside a final distribution board. The Construction line shares the same module width as other 1+N RCBOs in the Siemens 5SU series — no special busbar or adapter needed. Wire termination is screw-clamp; strip length and torque follow the printed markings on the device side. The D characteristic curve and type A residual-current module are factory-sealed — no field adjustment.