Line protection MCCB with ETU350 — what the ratings mean for your panel
The Siemens SENTRON 3VA2163-5HN36-0AE0 is a 3-pole molded case circuit breaker rated for line protection, carrying a continuous current Iu of 63 A that holds flat from 40 °C through 50 °C — no derating needed in a warm enclosure until you cross 55 °C, where it steps down to 60.6 A. The interrupting rating is the headline here: 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. That 187 kA figure at 240 V means this breaker handles high-fault scenarios common on the secondary side of large distribution transformers without needing a current-limiting upstream device — it's sized for switchboard and main feeder duty, not just branch protection. The ETU350 electronic trip unit gives you adjustable long-time, short-time, and instantaneous pickup settings plus ground-fault alarm capability (though this variant ships without ground-fault monitoring fitted). Four HQ auxiliary switches come integrated, so you get status feedback without bolting on an external accessory block.
Mounting and integration — DIN-rail or panel-mount, IP40 front
Dimensions are 105 mm wide, 181 mm tall, 86 mm deep — standard SENTRON 3VA2 footprint that drops into existing panel cutouts or onto the mounting plate without re-drilling. The IP40 front protection means it's splash-safe from the front face in a closed enclosure; the busbar connections and terminals are inside the panel, not exposed. Rated insulation voltage Ui is 800 V, so it's comfortable on 480 V and 600 V class systems with margin. Maximum power loss is 4 W — negligible for thermal budgeting inside a crowded cabinet. Operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C. The mechanical endurance is 20,000 operations — that's the latching mechanism life, not the electrical switching life under load.