SENTRON 3VA2 MCCB with ETU310M — 25 A, 3-Pole, High Interrupting Capacity
The Siemens 3VA2125-7MS36-0AA0 is a SENTRON 3VA2 series molded case circuit breaker rated for a continuous current of 25 A across the full ambient range from 40 °C to 70 °C — no derating needed up to that ceiling. The 3-pole frame carries an ETU310M electronic trip unit with an adjustable short-circuit pickup (Ii) from 75 A to 375 A, letting you fine-tune magnetic protection for motor or feeder duty without swapping the breaker. Interrupting capacity is the headline here: 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 3.8 kA at 690 V. That SCCR headroom means this breaker can sit upstream of a high-fault panel or transformer secondary without cascading — it clears the fault before the main sees it. The insulation voltage (Ui) is rated 800 V, so the 690 V rating is within the design envelope, not a derated stretch.
Panel Fit — Footprint and Mounting
The breaker measures 105 mm wide, 181 mm high, and 86 mm deep — a standard 3-pole MCCB footprint that fits most 600 V panelboards and enclosure backpanels without a subplate adapter. Front IP40 protection means it is suited for indoor switchgear; no washdown rating, so keep it out of hose-down zones. Maximum power dissipation is 75 W at rated load — factor that into enclosure thermal rise calculations if grouping multiple breakers in a sealed cabinet.
Trip Unit and Adjustability
The ETU310M is a basic electronic trip unit — no communication, no phase-failure detection, no ground-fault monitoring. What it does give you is an adjustable short-circuit pickup (75 A to 375 A) and a fixed thermal memory. For a motor branch circuit, set the Ii to 8–10× FLA to ride through inrush; for a feeder, the lower end of the range provides tighter protection against bolted faults. The 25 A continuous rating holds flat across the ambient range, so no summer-derating headache in a warm panel.