MCCB for main feeders and heavy branch protection
The Siemens SENTRON 3VA1220-6EF42-0BA0 is a 4-pole molded case circuit breaker rated for 200 A continuous current (Iu) with a TM240 thermal-magnetic overcurrent release. It carries an undervoltage release (UVR) as the auxiliary trip, model 3VA9608-0BB11, so the breaker drops open on loss of control voltage — a common requirement for emergency-stop circuits or undervoltage protection schemes. Breaking capacity varies sharply with system voltage: 220 kA at 240 V, 154 kA at 415 V, 36 kA at 440 V, and 17 kA at 690 V. At 415 V this breaker handles fault currents up to 154 kA — enough for most industrial main switchboards and large sub-distribution boards where high available fault current is a concern. Rated insulation voltage is 800 V, so it can be applied on 690 V systems (common in mining, oil & gas, and heavy industrial plants) without series-derating for voltage withstand.
Thermal derating and panel fit
The breaker carries full 200 A from 40 °C through 50 °C ambient. Above that, the TM240 release derates: 194 A at 55 °C, 188 A at 60 °C, 182 A at 65 °C, 176 A at 70 °C. If the panel ambient runs hot — say near a transformer or drive cabinet — size the upstream conductor and bus for the derated value, not the nameplate 200 A. Dimensions are 140 mm wide × 158 mm high × 70 mm deep. That 70 mm depth is shallow enough for standard 200 mm deep enclosures, leaving room for cable bending radius behind the breaker. The front face carries IP40 protection — fine for a clean indoor panel, but not for washdown or outdoor exposure without an additional enclosure. No auxiliary contacts or communication module are fitted on this variant. The UVR coil is the only auxiliary. If you need remote status or shunt trip, you'll add the external accessory block separately.
Selectivity and coordination note
The TM240 release is a thermal-magnetic design with a fixed thermal curve for overload and magnetic for short-circuit. No electronic adjustment or zone-selective interlocking. Operating temperature range is -25 °C to +70 °C; storage range -40 °C to +80 °C. The storage limit matters for spares kept in unheated warehouses — fine down to -40 °C, which covers most climates.