125 A, Curve C — the MCCB alternative on a DIN rail
That 125 A rating puts it above the typical 63 A ceiling of standard miniature circuit breakers — it bridges into territory where a panel builder would otherwise reach for a molded-case breaker. The 50 kA interrupting capacity at 230 VAC means it handles high-fault-current scenarios without cascading upstream, which simplifies coordination studies on a distribution board. DIN rail mounting keeps it in the same panel footprint as the rest of the S800 family, so no extra bracketing or busbar work.
Trip Curve C means the magnetic trip threshold is 5 to 10 times the rated current — so for this 125 A breaker, instantaneous trip starts between 625 A and 1250 A. That suits general-distribution loads like lighting banks, small motor groups, and resistive heaters where inrush isn't extreme. For a 3-pole configuration on a 230 VAC line, that's typically a line-to-neutral or line-to-line fault scenario in a three-phase distribution panel.
DIN rail integration note
The S800S body width for a 3-pole unit is 3 x 17.5 mm = 52.5 mm, which matches the modular pitch of most distribution boards. No special busbar adapters needed — the line and load terminals accept standard pin or fork busbars from the S800 accessory range. Keep the ambient temperature inside the enclosure below 40 °C for full 125 A rating; derate per the thermal curve above that.