MCCB for High-Fault Line Protection
Above that, derating is linear: 241 A at 55 °C, 232 A at 60 °C, 222 A at 65 °C, and 213 A at 70 °C. For panel builders, this means the 250 A frame can serve a 250 A load only if the enclosure ambient stays at or below 50 °C; above that, the load must be reduced per the derating curve. Maximum power loss is 48 W.
SCCR values by system voltage: 330 kA at 240 V, 242 kA at 415 V, 242 kA at 440 V, 187 kA at 500 V, and 4.5 kA at 690 V. The steep drop at 690 V (4.5 kA) is typical for this class — the breaker is optimized for 240–500 V networks. For a 690 V installation, verify the available fault current does not exceed 4.5 kA, or select a higher-rated frame.
Physical Dimensions and Panel Fit
Dimensions: 181 mm height, 105 mm width, 86 mm depth. The 86 mm depth (3.39 inches) leaves clearance for rear-connected bus bars or cable lugs.