What this MCCB is and what it carries
The Siemens 3VA2325-5HN32-0AD0 is a SENTRON molded case circuit breaker (MCCB) configured for line protection — the primary role is protecting cables and distribution bus against overload and short circuit in a main or sub-feed panel. It is rated for a continuous current Iu of 250 A, with the ETU350 electronic trip unit governing the time-current curve. The 3-pole construction handles three-phase systems up to 800 V rated insulation voltage Ui.
Breaking capacity — what the voltage columns tell you
This MCCB delivers 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 17 kA at 690 V. That 187 kA figure at 240 V is high for a 250 A frame — it means the breaker can interrupt a massive fault on a low-voltage secondary without the arc flashing over. At 690 V the 17 kA is still adequate for most industrial motor circuits; the drop-off is typical of a compact MCCB where arc extinction gets harder as voltage climbs. For a panel builder, the 415 V / 121 kA rating is the one that governs most European and Asian distribution boards — it clears a bolted fault on a 400 V bus without needing an upstream current-limiting fuse.
Thermal derating and panel integration
The breaker carries its full 250 A from 40 °C through 50 °C ambient — no derating needed in a typical ventilated enclosure. At 55 °C it steps down to 240 A, at 60 °C to 235 A, and at 70 °C to 225 A. That 37.5 W maximum power loss at rated current means the heat dissipated inside the enclosure is modest; a standard steel gland plate with natural convection handles it, though a crowded panel with multiple breakers side-by-side should be checked for cumulative thermal rise. Dimensions are 248 mm high, 138 mm wide, 110 mm deep — the 138 mm width is the 3-pole frame footprint, so it occupies three adjacent 45 mm module positions on a DIN rail or mounting plate.
Auxiliary contacts and trip unit detail
This variant ships with three auxiliary switches HQ — that is a factory-fitted set of changeover contacts for remote status indication (open/closed/tripped). The ETU350 electronic trip unit provides adjustable overload (Ir) and short-circuit (Isd) thresholds plus a ground-fault alarm function; it is the mid-range electronic trip in the 3VA2 family, sitting between the basic thermal-magnetic and the full-communications ETU600. No undervoltage release, no shunt trip, and no communication module are included on this order code — those are added via the integrated auxiliary trip slot (factory-fitted with 3VA9608-0BB24).