The Siemens 5SU1353-7KV20 is a Type A residual current circuit breaker with integral overcurrent protection (RCBO) in a 1+N-pole form factor. It combines a 30 mA residual-current trip with a C-curve 20 A overcurrent characteristic, rated for a 4.5 kA short-circuit breaking capacity. The Type A designation means it detects pulsating DC fault currents as well as sinusoidal AC — necessary on circuits with single-phase rectifiers, switched-mode power supplies, or variable-speed drives that can generate smooth DC fault components.
The 1+N-pole construction switches both phase and neutral, with the neutral pole opening after the phase pole and closing before it — a requirement in some national wiring rules.
Panel integration
The D=70 mm dimension matches the standard 70 mm depth of Siemens 5SU series RCBOs, fitting into the same distribution board cutouts and busbar systems as the rest of the family. The 1 module-width (18 mm) footprint on a DIN rail leaves room for adjacent devices in a crowded enclosure. Spring-loaded terminals accept 1.5–25 mm² conductors; strip length and tightening torque follow the manufacturer's installation instructions.