Its headline rating is 40 A at 480 V and 30 kA breaking capacity at 400 V — that 30 kA is the maximum fault current it can safely interrupt at 400 V, so on a 400 V line with a prospective short-circuit current up to 30 kA, this breaker clears the fault without upstream damage.
The breaker measures 55 mm wide and 149 mm deep, with a height of 140 mm. That 55 mm width is a single modular unit — it occupies one 55 mm slot on the DIN rail, leaving room for adjacent devices. Terminal capacity on the main contacts accepts 2x (1... 25 mm²) or 1x (1... 35 mm²) solid or stranded wire, with M6 screw terminals.