320 A MCCB with TM220 release — selectivity and SCCR headroom
The Siemens SENTRON 3VA1332-4EE32-0AA0 is a 3-pole molded case circuit breaker rated for 320 A continuous current at 40 °C ambient, with a TM220 thermal-magnetic overcurrent release. That TM220 designation means the thermal pickup is fixed at 320 A (the frame rating) and the magnetic short-circuit pickup is adjustable — typically 5–10× In, so 1 600–3 200 A instantaneous. This matters for panels mounted near heat sources or in non-climate-controlled enclosures — you size the copper and the enclosure ventilation for the actual ambient, not the nameplate. Breaking capacity is 121 kA at 240 V AC, dropping to 75.6 kA at 415/440 V, 52.5 kA at 500 V, and 11.9 kA at 690 V (–). That 121 kA at 240 V puts it in the high-interrupting category for North American 240/277 V distribution — suitable for large transformer secondaries or service-entrance applications where fault currents are high. At 415 V, the 75.6 kA covers most industrial main switchboard duties; the 690 V figure (11.9 kA) is the limiting case for 690 V drives or genset feeds. For DC networks, the manufacturer directs you to the 3VA device manual for switching power values.
At 138 mm wide (5.43 in) and 248 mm tall (9.76 in), it occupies roughly the same footprint as a 400 A frame from the same SENTRON family. Depth is 110 mm (4.33 in).
Lifecycle and sourcing — current production, quoted to order
No last-time-buy or phase-out notice is on record.
Comparison to 3VA1112-5EE32-0AA0 — frame size and breaking capacity delta
The closest functional sibling is the 3VA1112-5EE32-0AA0, also a 3-pole 320 A MCCB but on a smaller frame. The key difference: the 3VA1112 uses an electronic (ETU) release, giving adjustable long-time, short-time, and ground-fault protection. The 3VA1332-4EE32-0AA0 with its TM220 thermal-magnetic release is simpler, cheaper, and faster to trip on short-circuit, but offers no ground-fault or short-time delay adjustment.