The 5SU1154-1KV13 is a combined RCD/MCB (residual current device with miniature circuit breaker) in a single 1+N-pole module. The 10 mA IΔn (rated residual operating current) means it trips on earth leakage as low as 10 mA — that's the sensitivity you'd spec for personal protection in wet or medical-adjacent circuits, not just equipment protection. The C-curve (13 A rated current) handles moderate inrush from motor or lighting loads — it'll hold through a short startup surge without nuisance tripping, unlike a B-curve that would pop on the same load.
Deployment context
The 70 mm depth (D=70MM) is the overall module depth from the rail surface — check your enclosure depth clearance if you're retrofitting into a shallow box. The 1+N-pole format means it switches the line conductor and provides a switched neutral; standard for single-phase final circuits in TN or TT systems where you need both poles isolated.