What the ratings mean for the panel
The Siemens SENTRON 3VA1220-4GE42-0AA0 is a 4-pole molded case circuit breaker rated for 200 A continuous at 40 °C — that's the full-load current it can carry without tripping in a typical 40 °C panel ambient. The TM220 release means the thermal-magnetic trip is fixed at 200 A (the '220' code), so there's no adjustment dial; it's sized for a specific feeder or main. Breaking capacity hits 121 kA at 240 V, 75.6 kA at 415 V, and 52.5 kA at 440 V — figures that cover most low-voltage distribution fault levels in North American and IEC installations. At 690 V it still interrupts 11.9 kA, which matters for industrial systems with step-up transformers or VFD line reactors.
Thermal derating and enclosure fit
At 45 °C the breaker still holds 200 A; at 55 °C it derates to 194 A, at 65 °C to 182 A, and at 70 °C to 176 A. If the panel runs hot — say a non-ventilated enclosure near a furnace line — plan for the reduced ampacity. The footprint is 140 mm wide, 158 mm tall, and 70 mm deep, which fits standard SENTRON mounting patterns. IP40 on the front means it's protected against tools and wires >1 mm but not against water ingress; keep it inside the enclosure, not on a washdown wall.
What it protects and how it trips
Designed for line protection — feeder or main breaker duty in distribution panels. The TM220 release combines a thermal bimetal for overload (inverse-time, slow enough to start motors) and a magnetic coil for short-circuit (instantaneous above the magnetic pickup). No undervoltage release, no ground-fault monitoring, no communication function — it's a plain-vanilla thermal-magnetic breaker. Insulation voltage is rated 800 V, so it's suitable for 480/277 V and 600 V systems with margin. Power loss at full load is 42 W — factor that into enclosure cooling if you're packing multiple breakers in a tight cabinet.