What this 250 A MCCB delivers
It carries a 440 kA interrupting capacity at 240 V, dropping to 242 kA at 415 V and 440 V, 154 kA at 500 V, and 17 kA at 690 V — so it handles high available fault current on the low-voltage side of a distribution transformer without needing an upstream current-limiting fuse. The 3-pole design suits three-phase feeder or motor branch circuits in switchboards, panelboards, or standalone enclosures.
Thermal derating and temperature range
Above that, it derates: 245 A at 55 °C, 239 A at 60 °C, 234 A at 65 °C, and 228 A at 70 °C.
The 138 mm width is the critical panel cutout dimension — verify the mounting footprint against your existing switchboard or enclosure backplate before ordering. The 110 mm depth includes the case body; allow additional clearance for rear terminals and arc-chamber venting per the manufacturer's installation guide.