What the 1250 A AC-23A rating means for your distribution board
The C125S4WM is a ComPacT NS new generation switch disconnector basic frame — a 4-pole, manually operated, withdrawable unit rated for 1250 A in AC-23A duty across 220 V to 690 V AC at 50/60 Hz. AC-23A per IEC 60947-3 covers switching of motor loads and other highly inductive circuits, so this frame is sized for high-current distribution or motor control center incoming sections where you need to make and break loads under normal service conditions, not just isolate.
Withdrawable mounting and isolation capability
Withdrawable mounting means the moving portion can be racked out for safe maintenance without disturbing the power connections — a standard requirement for switchgear where you need visible isolation or quick swap-out. The unit is certified for isolation per IEC 60947-3, with a contact position indicator and an 8 kV rated impulse withstand voltage (Uimp). No visible break, so rely on the indicator and the withdrawable position for positive isolation confirmation.
Short-circuit performance and coordination headroom
Rated short-time withstand current (Icw) is 25 kA for 0.5 s and 4 kA for 20 s — the 25 kA figure governs selectivity with upstream breakers in a distribution cascade. For a site electrical engineer building a coordination study, these are the numbers that decide whether this frame holds under the upstream protective device's clearing time.
Environmental and mechanical durability
Mechanical durability is 10,000 cycles; electrical durability is 2,000 cycles at 440 V AC.