The Siemens 5SU1354-0KV25 is an FI/LS combination unit — an RCBO that packs both overcurrent protection and residual current detection into a single 70mm-wide module. It's a Type AC device rated for sinusoidal AC fault currents, with a 30mA trip threshold and 10kA breaking capacity. The B-curve 25A thermal-magnetic characteristic handles general-purpose and resistive loads without nuisance tripping on modest inrush.
What the ratings mean on the panel
The 30mA residual sensitivity is the standard for personnel protection in residential and light commercial final circuits — it catches leakage through the body before fibrillation risk becomes serious. The 10kA breaking capacity at the service entrance or sub-distribution board means this unit can clear a bolted fault up to 10kA without welding its own contacts shut. The B-curve (3-5x In magnetic trip) is the right choice for lighting, socket outlets, and general-purpose circuits; if you're feeding motor or transformer loads with higher inrush, you'd want a C-curve instead.
Integration note
The 70mm width occupies three standard 18mm DIN-rail modules. It snaps onto the DIN rail without tools and the tunnel terminals accept up to 25mm² conductor — common for the 25A feed-through. The Type AC designation means it detects only sinusoidal AC residual currents; if your circuit includes variable-speed drives, UPS systems, or LED drivers that generate pulsed DC fault currents, you need a Type A or Type F device instead.