Rated current and interrupting capacity — what they mean for your panel
The Siemens 3VA1340-5FF42-0AA0 is a SENTRON molded case circuit breaker (MCCB) rated for a continuous 200 A on a 4-pole frame, with a TM240 thermal-magnetic overcurrent release designed for line protection. The interrupting capacity is 187 kA at 240 V, 121 kA at 415/440 V, 75.6 kA at 500 V, and 11.9 kA at 690 V — so at typical 400 V distribution voltages it clears a 121 kA fault without cascading upstream. That SCCR headroom matters when you are coordinating a main breaker downstream of a transformer or tying into a high-capacity bus. Thermal derating is published: the breaker carries 400 A continuously at ambient temperatures from 40 °C to 50 °C, then steps down to 392 A at 55 °C, 384 A at 60 °C, 376 A at 65 °C, and 367 A at 70 °C. If your enclosure runs hot — say a packed panel near a furnace line — use the 55 °C or 60 °C column for sizing, not the 40 °C base.
Integration and mounting
The breaker measures 184 mm wide, 248 mm high, and 110 mm deep — a 4-pole frame that fits standard panel-mount cutouts for this class. Front protection is IP40, so it is suited for indoor switchgear and distribution boards where tools or fingers are unlikely to contact live parts. Rated insulation voltage is 800 V, which covers 480/600 V systems with margin.
Overcurrent release and power loss
The TM240 release is a fixed thermal-magnetic trip unit — no interchangeable electronic trip module, no communication function, no undervoltage release, and no ground-fault monitoring on this variant. Maximum power dissipation is 92.1 W at rated load, so factor that into your enclosure thermal budget if the panel is densely packed.