The Siemens SENTRON 3VA1050-4ED42-0AE0 is a 4-pole molded case circuit breaker (MCCB) rated for 50 A continuous current with a TM210 thermal-magnetic trip unit. It's designed for line protection in distribution panels, and the 121 kA breaking capacity at 240 V AC gives you serious fault-clearing headroom — let me show you why that matters for your coordination study. The TM210 trip unit means the thermal element is fixed at 50 A (the frame rating), and the magnetic pickup is adjustable from 5x to 10x In. That's a standard thermal-magnetic curve for feeder protection — no electronic adjustments, just reliable bimetal and solenoid action. If you're used to the older 3VL series, the 3VA platform shrinks the footprint while keeping the same interrupting ratings.
Breaking capacity at different voltages
This MCCB delivers 121 kA at 240 V AC, 75.6 kA at 415 V AC, 52.5 kA at 440 V AC, and 11.9 kA at both 500 V and 690 V AC. The steep drop above 500 V is typical for a 50 A frame — the arc energy scales with voltage, and the interrupter has limits. For a 480 V delta service (common in North American industrial), you're still above 50 kA, which covers most transformer-fed secondary faults. At 690 V, that 11.9 kA figure means you need to verify the available fault current at the panel — if it's higher, step up to a higher-frame 3VA.
Temperature derating and power loss
The breaker carries the full 50 A from 40 °C up to 50 °C ambient — no derating needed in a typical 40 °C panel. At 55 °C it drops to 49 A, at 60 °C to 48 A, at 65 °C to 46 A, and at 70 °C to 45 A. That's a gentle slope; you lose only 10 % at the max operating temperature. Maximum power loss is 14.6 W per pole, which is modest for a 50 A frame — helps keep the enclosure cool when you stack multiple breakers side by side.
Physical fit and aux switch configuration
Dimensions are 101.6 mm wide, 130 mm high, and 70 mm deep. The 4-inch width (101.6 mm) is the standard 4-pole MCCB footprint — it occupies four 25 mm module spaces on a DIN rail or panel-mount plate. The depth of 70 mm (2.76 in) is shallow enough that it clears most gland plates and back-panel wiring troughs. This breaker comes with 4 auxiliary switches (HQ type) pre-installed, so you get status feedback without adding external contact blocks. The basic switch variant is 3VA10504ED420AA0 — useful to know if you're ordering spare parts.
Environmental and operating limits
Operating temperature range is -25 °C to 70 °C, with storage from -40 °C to 80 °C. The insulation voltage is rated at 800 V, which covers 690 V line-to-line systems with margin. No communication function, no undervoltage release, no ground-fault monitoring on this variant — it's a straight thermal-magnetic breaker for basic feeder protection. If you need those extras, look at the 3VA1 with electronic trip or add-on modules.