ABB S203M-C63 S200M MCB, 63 A, Curve C, 3-Pole, DIN Rail

That curve C means it holds up to 5–10× rated current for short periods — standard for motor and transformer inrush on a general-purpose distribution panel, but not for pure resistive loads where a B curve would trip faster on a small overcurrent. Interrupting capacity is 6 kA at 277 VAC and 10 kA at 125 VDC. The AC figure tells you it handles fault currents up to 6,000 A on a 277 V line — enough for most sub-distribution boards fed from a transformer of 100 kVA or so. The DC rating at 125 V is higher because DC arcs are harder to extinguish; 10 kA gives a solid margin for battery-bank or UPS output circuits.