What this MCCB is and what it protects
The Siemens SENTRON 3VA1225-6EF32-0JC0 is a 3-pole molded case circuit breaker (MCCB) rated for a continuous current Iu of 250 A, built for line protection in distribution panels. It carries a TM240 thermal-magnetic overcurrent release — the thermal element handles overloads, the magnetic element handles short-circuits — and the breaker is designed to protect cables and busbars, not motor loads (no phase-failure detection, no undervoltage release fitted).
Breaking capacity — the real-world fault-handling range
Breaking capacity drops sharply as system voltage rises: 220 kA at 240 V, 154 kA at 415 V, 36 kA at 440 V, and 17 kA at 690 V. At 415 V it still clears 154 kA — that is well above typical industrial service-entrance fault levels — so this breaker suits high-fault panels where a standard 50 kA or 65 kA MCCB would not hold coordination. The 36 kA at 440 V is still a strong figure for 440 V distribution.
Thermal derating — what 250 A means at panel temperature
Rated continuous current is 250 A, and the breaker holds that rating flat from 40 °C through 50 °C. Above 55 °C it derates: 243.3 A at 55 °C, 236.5 A at 60 °C, 229 A at 65 °C, 223 A at 70 °C. If the panel ambient runs hot — say 55 °C inside a sealed enclosure — you lose about 7 A off the 250 A nameplate. The rated insulation voltage is 800 V, so the breaker is comfortable on 690 V systems.
Auxiliaries and accessories fitted
This variant ships with 2 auxiliary switches (HQ type) and a shunt trip release (STL) for remote tripping. The shunt trip order code is 3VA9688-0BL32 — if you need a spare or a replacement, that is the sub-component to order. No communication module, no ground-fault monitoring, no undervoltage release on this version. The front face carries IP40 protection — fine for a closed panel, not for open washdown areas.
Physical fit and panel integration
Dimensions: 105 mm wide, 158 mm tall, 70 mm deep. That is a standard 3-pole MCCB footprint for a 250 A frame — it will bolt into a SENTRON 3VA panel base or a universal mounting plate. No trip indicator on the front; the shunt trip and aux switches are the only wired accessories. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.