The Siemens 5SU9353-7CN32 is a 1P+N RCBO combining overcurrent and residual current protection in a single module. It carries a Type A residual current sensitivity of 30 mA and a C-Characteristic overcurrent trip curve, rated at 32 A on a 230 V AC supply with a breaking capacity of 4.5 kA. This is the unit for a single-phase final subcircuit where you need both earth leakage and short-circuit/overload protection in one DIN-rail footprint — common in commercial and light industrial distribution boards.
What the ratings mean for fit
The 30 mA Type A residual current rating means it detects sinusoidal AC faults plus pulsating DC fault currents — the standard requirement for circuits feeding electronics, variable-speed drives, or appliances with rectified loads. The C-Characteristic curve (10 to 15 times In magnetic trip) handles inrush from motor starters, lighting ballasts, or small compressors without nuisance tripping. The 4.5 kA breaking capacity at 230 V AC is sized for domestic and light commercial distribution boards where the prospective short-circuit current stays under that threshold; verify the upstream fault level before specifying.
Panel integration
Snap-on DIN rail mount for standard 35 mm profile. Single-module width saves rail space in a crowded enclosure. The 1P+N configuration switches the line conductor and provides neutral switching on the outgoing side — check that your distribution board's neutral bar arrangement matches this topology.