What it is and what it does
The Siemens 3VA1150-4EF36-0DA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels and motor control centers. It carries a 50 A continuous rating at 40 °C with a thermal-magnetic TM240 overcurrent release, so the breaker holds at 50 A and trips on sustained overload or short-circuit — no communication module or ground-fault monitoring on this variant. Three-pole construction with an undervoltage release (UVR) built in: if the control voltage drops, the UVR trips the breaker open — a standard requirement for safety disconnects on machine feeders where loss of control power must interrupt the load.
Breaking capacity — the real coordination number
Rated short-circuit breaking capacity (Icu) reaches 121 kA at 240 VAC, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 500 V or 690 V. The 415 V figure is the one most panel builders will coordinate against for 400 V three-phase distribution — 75.6 kA gives headroom for high-fault service-entrance positions without cascading upstream. Rated insulation voltage is 800 V, so the breaker is electrically rated for 690 V systems with margin. The TM240 release is a fixed thermal-magnetic type — no electronic adjustment or trip-indicator flag on this order code.
Thermal derating and panel fit
The 50 A rating holds flat from 40 °C to 50 °C, then derates to 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. In a sealed panel with internal ambient above 50 °C, size the continuous load at 45 A to avoid nuisance tripping. Maximum power loss is 17.1 W — negligible for enclosure heat-budget calculations but worth noting if the panel is densely packed. Dimensions: 130 mm high, 76.2 mm wide, 70 mm deep — a standard 3-pole MCCB footprint that drops into most SENTRON and third-party distribution blocks without re-drilling the mounting plate. Operating range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.