What this MCCB is and what it does
The Siemens 3VA1050-4ED42-0JA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection — the primary feeder or distribution circuit, not a motor-protective device. It carries a 50 A continuous rating across the 40 °C to 50 °C ambient range, then begins to derate: 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. That means in a hot panel you lose headroom fast — plan your load at 45 A if the enclosure sits near its upper operating limit. The 4-pole construction handles three-phase plus neutral switching, common in North American and European distribution panels where the neutral needs isolation or where downstream loads share a common neutral bar. The TM210 overcurrent release is a thermal-magnetic type — thermal element for overload protection, magnetic coil for short-circuit response. No electronic adjustment, no communication module, no ground-fault monitoring on this variant. Breaking capacity is the headline number that decides whether this breaker clears a fault or welds shut. At 240 V it interrupts 121 kA; at 415 V it drops to 75.6 kA; at 440 V it is 52.5 kA; at 500 V and 690 V it holds at 11.9 kA. If your available fault current at the panel exceeds these values at the system voltage, this breaker is not the right choice — step up to a higher-rated frame. The rated insulation voltage is 800 V, so the internal clearances support 690 V systems.
Shunt trip and physical fit
This order code includes a shunt trip (STL) auxiliary release — a separate coil that trips the breaker when energized, typically wired to an emergency-stop button, a remote relay, or a safety PLC output. The shunt trip is factory-installed; no field retrofit. There is no undervoltage release on this unit, so a loss of control power does not automatically open the breaker. Dimensions are 130 mm height, 101.6 mm width, 70 mm depth. The 4-pole width is wider than a 3-pole frame — verify the DIN-rail or mounting-plate space before committing the panel layout. The supplied basic switch is order code 3VA10504ED420AA0, which is the internal switching mechanism; the complete breaker ships as one assembly.