What this MCCB is and what it does
The Siemens SENTRON 3VA1032-4ED42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for 32 A continuous current (Iu), fitted with a TM210 thermal-magnetic overcurrent release. The TM210 release combines a thermal bimetal for overload protection and a magnetic coil for short-circuit protection — the '210' designates the fixed magnetic trip threshold at 10× In (320 A, adjustable down to 320 A as the li max setting). This part is line-protection version (no ground-fault monitoring, no N-conductor protection, no communication function).
Breaking capacity — the real-world fault current limits
This MCCB's interrupting capacity varies sharply with system voltage, and the buyer needs to match it to the available fault current at the panel's point of common coupling. At 240 V it breaks 121 kA — a very high rating for a 32 A frame, suitable for large transformer secondaries or bus-duct feeds. At 415 V it still handles 75.6 kA; at 440 V it drops to 52.5 kA; at 500 V and 690 V it holds at 11.9 kA. The 690 V figure is the same as the 500 V figure, which suggests the arc extinction limits the rating above 500 V, not the mechanical capacity. For a 400 V distribution board with a 50 kA prospective fault, this breaker has headroom.
Thermal derating — how hot can the panel run?
The continuous current rating is 32 A at 45 °C and 50 °C ambient. At 55 °C it derates to 31 A, at 60 °C to 31 A, at 65 °C to 30 A, and at 70 °C to 30 A. That is a shallow derating curve — only 2 A lost from 45 °C to 70 °C — which means the thermal element is well-sunk into the frame. If the panel ambient stays under 50 °C, you get full 32 A. The maximum operating temperature is 70 °C; storage range is -40 °C to 80 °C.
Dimensions and panel fit
The 3VA1032-4ED42-0AA0 measures 70 mm deep, 101.6 mm wide, and 130 mm tall. The 70 mm depth is standard for the 3VA1 frame — it fits most 200 mm deep enclosures with room for rear-access wiring. The 101.6 mm width (4 inches) for a 4-pole breaker is compact; expect a 4-module-wide cutout on a DIN-rail adapter plate. Front IP40 rating means tools and fingers are safe, but not hose-down.
Electrical ratings and power loss
Rated insulation voltage Ui is 800 V AC; maximum operational voltage for DC circuits is 600 V. Maximum power loss at rated current is 10.6 W — that is the heat the breaker dumps into the enclosure. In a sealed panel with multiple breakers, that heat adds up; plan ventilation if the total dissipation exceeds the cabinet's natural convection capacity.