What this MCCB is and what it does
The Siemens 3VA2110-7MS36-0DC0 is a SENTRON molded case circuit breaker (MCCB) built for starter protection — meaning it's designed to sit ahead of a motor contactor and protect the branch circuit and the motor itself against short circuits and overloads. It's rated 100 A continuous at 40 °C, and carries a massive 330 kA breaking capacity at 240 V AC. That 330 kA figure tells you this breaker can safely interrupt a fault current up to that level without welding its contacts or rupturing — it's sized for high-fault installations like large transformer secondaries or heavy industrial feeders where the available fault current is extreme. The 3-pole construction handles three-phase loads, and the electronic ETU310M release gives you adjustable overload and short-circuit protection curves, which is what you want when you're coordinating with a motor starter downstream.
Breaking capacity across voltages — the real-world numbers
Breaking capacity isn't one number; it changes with system voltage. At 415 V and 440 V it's rated 242 kA, at 500 V it drops to 187 kA, and at 690 V it's still a respectable 52.5 kA. If you're feeding a 480 V panel in North America or a 400 V distribution in Europe, the 242 kA figure is the one that governs your SCCR calculation. The 690 V rating is useful for 600 V class Canadian installations or certain mining applications. Always size the breaker so the available fault current at the point of installation does not exceed the rating at your system voltage.
Thermal derating — don't lose capacity in a hot panel
This MCCB is rated a full 100 A from 40 °C up to 50 °C. At 55 °C it derates to 96 A, at 60 °C to 94 A, at 65 °C to 92 A, and at 70 °C to 90 A. If your panel runs hot — say next to a furnace line or inside a non-ventilated enclosure — you need to account for that derating. The maximum operating temperature is 70 °C, and storage range is -40 °C to 80 °C. Power loss at full load is 75 W maximum, which adds to your enclosure's thermal budget.
Built-in undervoltage release and auxiliary switches
This order code includes an undervoltage release (UVR) — part number 3VA9608-0BB25 — which trips the breaker when supply voltage drops below a threshold. That's common in safety circuits where you want the breaker to drop out on a control-voltage loss. It also comes with 2 HQ auxiliary switches (form C contacts) for status feedback to a PLC or indicator lamp. The basic switch assembly is order code 3VA2110-7MS36-0AA0, so if you ever need to replace just the switching mechanism, that's the spare. Mechanical endurance is rated at 20,000 operations.