The Siemens SENTRON 3VA2440-6HL32-0KL0 is a 3-pole molded case circuit breaker rated for 400 A continuous at ambient temperatures from 40 °C through 70 °C without derating — the full 400 A holds across that entire thermal band, so a warm panel doesn't force a downsized breaker. Its adjustable thermal-magnetic trip unit covers 600 A minimum to 4 800 A maximum, giving the specifying engineer a wide window to coordinate with downstream protection without swapping the breaker frame. Short-circuit interrupting ratings scale with system voltage: 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 9 kA at 690 V — the 242 kA figure at 240 V is the headline number for high-fault industrial services where the available fault current is substantial.
This is a line-protection design (not motor-protection or ground-fault), so it is the right choice for feeder and main breaker duty where the primary concern is cable and bus protection.