What this MCCB carries and where it fits
The Siemens 3VA1332-6GF42-0AA0 is a SENTRON molded case circuit breaker (MCCB) rated for line protection, with four poles and a TM240 thermal-magnetic overcurrent release. It is rated 320 A continuous at 40 °C ambient and delivers a 220 kA interrupting capacity at 240 V AC — that is the headline figure for fault clearing on a high-capacity service entrance or a large feeder in an industrial distribution panel. At 415 V the breaking capacity is still 154 kA, and it holds 121 kA at 500 V, so it handles substantial fault current across common low-voltage networks. The 800 V rated insulation voltage confirms it is built for 690 V systems with margin.
Derating and thermal behaviour in the panel
The 320 A rating holds flat from 40 °C to 50 °C. Above that it derates linearly: 313 A at 55 °C, 306 A at 60 °C, 299 A at 65 °C, and 292 A at 70 °C (–). If this breaker sits in a non-ventilated enclosure alongside other heat sources, the 55 °C or 60 °C row is the one to size against — the thermal-magnetic trip element responds to internal temperature, so a hot panel reduces the headroom before nuisance tripping. Maximum power loss is 80.1 W, which is moderate for a 320 A frame; factor that into the enclosure thermal calculation. Physical dimensions are 248 mm high, 184 mm wide, 110 mm deep. The front face carries an IP40 protection class.
Selectivity and coordination notes
The TM240 release is a fixed thermal-magnetic trip — no electronic adjustment, no communication module, no ground-fault monitoring.