What it is and what it does
The Siemens 3VM1340-5EE42-0AA0 is a 4-pole IEC frame 400 molded-case circuit breaker rated for line protection. Its TM220 thermal-magnetic release gives an overload pickup adjustable from 280 A to 400 A (Ir) and a fixed short-circuit pickup at 10 × In (Ii = 4000 A). The 55 kA Icu at 415 V means it can safely interrupt a fault current up to that level without welding its contacts or rupturing the case — that is the breaking capacity class S rating, sized for high-fault industrial distribution panels where the available short-circuit current is substantial.
Panel integration and wiring
The 261 × 208 × 170 mm package fits standard IEC panel-mount cutouts for frame-400 breakers. The nut keeper kit (included) holds the mounting nuts captive during installation — a small detail that saves time when you are working alone inside a live panel. The N conductor is unprotected on this variant, so if you need a fully protected neutral, this is not the order code for that scheme.
Compliance and documentation
RoHS compliant since 01 June 2012. REACH Article 33 disclosure: the part contains lead (CAS 7439-92-1) above 0.1% w/w in the candidate list. Export control is AL:N / ECCN:9N9999 — no special license required for most destinations.