Line protection MCCB with ETU350 — what the interrupting ratings mean for your panel
The Siemens SENTRON 3VA2110-5HN36-0BH0 is a 3-pole molded case circuit breaker rated for line protection, carrying a continuous current Iu of 100 A at 40 °C through 50 °C, then derating to 85 A at 70 °C. The ETU350 electronic trip unit provides adjustable overload and short-circuit protection without a voltage trigger — it's a self-powered release, so no auxiliary control power is needed for the trip function. What sets this MCCB apart is the interrupting capacity: 187 kA at 240 V, 121 kA at 415 V and 440 V, 79 kA at 500 V, and 4.25 kA at 690 V. Those figures mean it can safely clear a fault at the full available short-circuit current of a high-capacity transformer secondary without the arc re-striking or the case rupturing — critical for a main or feeder breaker in a 240 V or 415 V distribution panel where the upstream transformer is sized for high fault current.
Thermal derating and endurance — the real-world operating envelope
The 100 A rating holds flat from 40 °C to 50 °C ambient; above that, the continuous current must be reduced per the datasheet curve — 96.25 A at 55 °C, 92.5 A at 60 °C, 88.75 A at 65 °C, and 85 A at 70 °C. If the panel ambient runs above 50 °C, size the load accordingly. The latching endurance is rated at 20,000 operations — that's the mechanical life before the latch mechanism wears, not the electrical endurance under load. For frequent switching, factor in the electrical life at your specific fault level. The maximum power loss is 12.5 W, which matters for heat buildup inside a sealed enclosure.
Built-in undervoltage release and auxiliary contacts
This variant includes an integrated undervoltage release (UVR) — part number 3VA9608-0BB11 for the auxiliary trip module — so the breaker trips when control voltage drops below the dropout threshold. The auxiliary contact configuration is 2 auxiliary switches plus 1 trip alarm switch (HQ version), giving you status feedback for the open/closed position and a separate alarm contact that changes state only on a trip event. That alarm contact is useful for remote fault annunciation without wiring through the main breaker position. The basic switch assembly is orderable separately as 3VA2110-5HN36-0AA0 if you need a replacement mechanism.
Physical footprint and panel fit
Dimensions: 181 mm height, 105 mm width, 86 mm depth. The width of 105 mm is the standard 3-pole MCCB footprint for this SENTRON frame size — it occupies three 35 mm DIN-rail modules plus a small margin. The depth of 86 mm includes the arc chamber and terminal clearance; verify that the enclosure depth leaves room for cable bending radius behind the breaker. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.