The Siemens 5SU1356-0DA25 is an FI/LS protector (RCBO) combining overcurrent protection and residual current detection in a single 1+N-pole module. It is rated B-curve 25A for overcurrent, with a residual sensitivity of 30mA (Type AC) and a breaking capacity of 6kA. The 70mm width and pigtail connection suit standard distribution board layouts where space is allocated per DIN rail module count.
The B-curve 25A rating means the unit trips magnetically at 3 to 5 times rated current (75–125A) — appropriate for resistive and general-purpose loads, but not for high-inrush motor circuits where a C- or D-curve would be needed.