What it is and what it does
The Siemens 3VA1340-6EF32-0AB0 is a SENTRON molded case circuit breaker (MCCB) built for line protection — the main disconnect and fault interrupter between a transformer or bus and a downstream distribution panel. Three poles, rated 400 A continuous at 40 °C, with a TM240 thermal-magnetic trip unit that handles overload and short-circuit protection in one package. Breaking capacity is the headline number here: 220 kA at 240 V AC, 154 kA at 415/440 V, 121 kA at 500 V, and 17 kA at 690 V. That 220 kA at 240 V means it can safely interrupt a fault current up to 220,000 amps without welding contacts or rupturing the case — critical for high-fault locations like transformer secondaries or large motor control centers where available fault current is high. The 17 kA at 690 V is the weak point; if your system runs 690 V and fault current exceeds that, you need a current-limiting upstream device or a different frame.
Ratings that matter for fit
Continuous current is 400 A flat from 40 °C through 50 °C, then derates to 392 A at 55 °C, 384 A at 60 °C, 376 A at 65 °C, and 367 A at 70 °C. If your panel ambient runs 55 °C or higher, the 400 A label doesn't hold — size the load at the derated figure or move to a higher-frame breaker. Insulation voltage is rated 800 V, so the breaker is electrically rated for 690 V systems even though the interrupting capacity drops at that voltage. Power loss at full load is 92.1 W maximum — that's heat that stays inside the enclosure. In a sealed panel with multiple breakers, that thermal load adds up; factor it into the cabinet cooling calculation or you'll cook the trip unit. Operating temperature range is -25 °C to +70 °C, storage from -40 °C to +80 °C. The storage range is wider because there's no current flowing — that's the handling and warehouse limit, not the running limit.
Lifecycle and sourcing reality
This breaker is current production. Quoted and sourced to order against an RFQ through independent distribution.
Panel integration notes
Dimensions: 248 mm high, 138 mm wide, 110 mm deep. That 138 mm width is the standard 3-pole MCCB footprint for this frame size — it fits Siemens' own mounting accessories and most DIN-rail or backplate layouts designed for 3VA frames. The 110 mm depth means it projects less than many older frames, which helps in shallow enclosures. The breaker ships with a basic switch (order code 3VA13406EF320AA0) and two auxiliary switches (HP type) for status feedback to a PLC or indicator lamp. No undervoltage release, no ground-fault monitoring, no communication module on this variant — those are add-on options if needed.