The 400 A rating holds across 40 °C to 50 °C ambient without derating — at 55 °C it's still good for 385 A, and at 70 °C it carries 340 A, so it handles warm panel environments without stepping up frame size. Breaking capacity hits 330 kA at 240 V, 242 kA at 415/440 V, 187 kA at 500 V, and 52.5 kA at 690 V — that's serious fault-interruption headroom for high-capacity distribution or transformer secondary protection where available fault current is high. It's a straight overcurrent protector with a trip indicator, suited for fixed-distribution or feeder duty where you don't need metering or remote signaling beyond the auxiliary contact block.
Maximum power loss is 96 W at rated load, so adjacent devices need breathing room; don't pack it tight against heat-sensitive electronics without checking the thermal stack.