The Siemens 3VA1340-5GE42-0AA0 is a 4-pole SENTRON molded case circuit breaker rated 400 A continuous at 40 °C with a TM220 thermal-magnetic trip unit. The 400 A frame carries full current up to 50 °C before derating begins — at 55 °C it's still 392 A, at 70 °C it's 367 A — which gives you thermal headroom in a warm enclosure. The TM220 designation means a thermal-magnetic overcurrent release with a fixed thermal pickup and magnetic short-circuit trip.
The 3VA1340-5GE42-0AA0 measures 248 mm high by 184 mm wide by 110 mm deep. The 4-pole footprint with 100 % N-conductor protection means the neutral pole is fully rated and switches with the phases — no derating for the neutral path. Front IP40 protection keeps dust and tools out of the mechanism.
Interrupting capacity by voltage — what the numbers mean
At 415/440 V it's still 121 kA, which covers most industrial low-voltage switchgear. At 500 V it drops to 75.6 kA, and at 690 V to 11.9 kA — still adequate for 690 V motor circuits but not for high-fault 690 V buswork.