The 2CCS891001R0104 is a 1-pole miniature circuit breaker (MCB) with a C-curve trip characteristic, rated 10 A continuous current. The 25 kA rated short-circuit breaking capacity (Icn) tells you it can safely interrupt a fault up to 25 kA under standard conditions; the 36 kA ultimate breaking capacity (Icu) is the maximum it can break once and still function after. For most commercial and light industrial panelboards fed by a transformer of 400 kVA or less, 25 kA Icn is sufficient — but if your fault current study shows higher, the 36 kau Icu gives you a safety margin for the one-shot event.
The 27 mm width (1-module) means it occupies a single pole position in a distribution board — tight for retrofit where panel space is already allocated. Screw terminals accept up to 3.5 Nm torque, which is typical for 10 A branch circuits; use a torque screwdriver to avoid terminal heating. IP20 finger-safe rating means it's protected against solid objects larger than 12.5 mm (fingers) but not against moisture — install inside a panel or enclosure with a higher IP-rated door.
Voltage and overvoltage class
Rated insulation voltage of 690 V means the internal clearance and creepage distances are designed for 690 V phase-to-phase systems — common in 400/690 V industrial grids (e.g., IT systems or delta-connected supplies). Overvoltage category IV means it's rated for installation at the origin of the installation (main distribution board), where transient overvoltages are highest. That's a step above the usual Cat III for sub-distribution.