What this 40 A MCCB delivers — and what the ratings actually mean for your panel
The Siemens SENTRON 3VA2140-5HN42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for 40 A continuous current across the full ambient range from 40 °C to 70 °C — no derating needed up to that ceiling, which simplifies panel build in warm enclosures or near heat sources. Its ETU350 electronic trip unit provides adjustable overload and short-circuit protection curves, with N-conductor protection configurable to OFF or 100 % — a feature that matters when you need to protect a fully rated neutral in a 4-wire system. Breaking capacity hits 187 kA at 240 V AC and 121 kA at 415/440 V, tapering to 75.6 kA at 500 V and 3.7 kA at 690 V — the 690 V figure is low enough that you need to verify coordination upstream if the service voltage sits near that ceiling. Rated insulation voltage is 800 V, and the front face carries IP40 protection — fine for a clean indoor panel, but not for washdown zones.
Panel fit and integration notes
Dimensions are 181 mm height, 140 mm width, 86 mm depth — standard SENTRON 3VA footprint for a 4-pole frame at this rating. No undervoltage release, no voltage trigger, no communication module, and no ground-fault monitoring on this variant — it is a straight line-protection breaker with the ETU350 trip unit and a mechanical trip indicator absent. Power loss is rated at 1.6 W maximum — negligible for thermal budgeting inside a crowded panel.