Siemens 3VA10 Series

The 3VA10 Is Siemens' Workhorse Molded Case Circuit Breaker Line — Up to 1600 A, No Frills, Just Trip Curves That Hold

The 3VA10 series sits at the entry tier of Siemens' 3VA molded case circuit breaker (MCCB) family. It covers 160 A through 1600 A frame sizes in 3-pole and 4-pole configurations, with interrupting ratings from 25 kA to 100 kA at 480 V. These are IEC 60947-2 breakers — thermal-magnetic or basic electronic trip units, no LCD, no comms module, no onboard metering. If you need Modbus or power quality logging, that is the 3VA2 line. The 3VA10 is what you spec when the budget says "protect the feeder and move on."

The trip unit choices define what you get out of this series. The TM (thermal-magnetic) units handle standard overload and short-circuit protection with fixed thermal and adjustable magnetic thresholds. The ETU350 electronic trip unit adds adjustable long-time, short-time, and instantaneous pickup — same LS-I curve family you would find on the 3VA2, minus the ground-fault element and the display. That means the 3VA10 with an ETU350 can do selective coordination in a multi-tier distribution scheme, just without the waveform capture or event logging that the 3VA27 trip unit brings.

Typical installations: feeder protection in low-voltage switchgear (Siemens SIVACON S8 or third-party IEC 61439 panels), incoming mains on 400 V distribution boards for light industrial buildings, motor feeder protection when paired with a separate overload relay, and generator output breakers where the adjustable short-time delay prevents nuisance tripping on inrush. You also see these in HVAC chiller plant disconnects — the 100 kA interrupting rating at 480 V covers installations close to the service transformer without needing a current-limiting fuse upstream.

Trip Unit Comparison: 3VA10 ETU350 vs 3VA2 ETU350

The trip unit electronics themselves are identical silicon — Siemens did not build two different ETU350s. The 3VA10 simply omits the HMI, the metering board, and the connector for the communication module. If your panel already has a branch-circuit power meter downstream, paying for a metering-capable breaker is redundant. That is the sweet spot for the 3VA10.

Key Selection Parameters

Picking the Right Variant

Frame size is driven by the load current, not the upstream available fault current — size the frame to the load, then pick the interrupting rating based on the prospective short-circuit current at the installation point. A common mistake is oversizing the frame for the interrupting rating. Siemens has a 250 A frame with 100 kA Icu; you do not need to jump to the 400 A frame for the rating unless the load demands it.

For motor feeders, the thermal-magnetic TM unit with adjustable magnetic pickup between 5-10× In handles inrush from across-the-line starts on motors up to roughly 200 kW. Above that, the ETU350's adjustable short-time delay (with I²t slope option) gives you the curve-shaping to ride through starting current while still catching a bolted fault downstream.

On price: the 3VA10 undercuts the 3VA2 by roughly 40-60% for equivalent frame sizes. Where you lose out is reusability — the 3VA2 lets you swap trip units in the field without removing the breaker from the bus. The 3VA10 trip unit is factory-installed and not field-replaceable. Plan your protection scheme before you order.

Procurement Notes

Siemens distributes the 3VA range through their standard electrical distribution channel — Rexel, Sonepar, Graybar in North America, and regional Siemens partners in EMEA and APAC. Lead times on standard TM configurations are typically 2-4 weeks from regional DC stock. ETU350 variants and 4-pole frames can stretch to 6-8 weeks depending on the configuration. The 3VA10 shares the same mounting footprint and bus connection pattern as the 3VA2 in equivalent frame sizes, so upgrading later is mechanically straightforward — the bus work does not change.