Siemens 3VA1450-6EF32-0DF0 — 500 A SENTRON MCCB with TM240 release
The Siemens 3VA1450-6EF32-0DF0 is a SENTRON molded case circuit breaker (MCCB) rated for 500 A continuous current at 40 °C, in a 3-pole configuration. Its TM240 thermal-magnetic overcurrent release provides fixed thermal and magnetic trip settings — the thermal element handles overload protection, the magnetic element covers short-circuit protection up to the breaker's interrupting rating. Breaking capacity is 220 kA at 240 V AC, 154 kA at 415 V and 440 V, 121 kA at 500 V, and 17 kA at 690 V. That 220 kA figure at 240 V places this breaker in the high-interrupting category — it can clear faults on the secondary side of a large distribution transformer without cascading to upstream protection. The 17 kA at 690 V still covers most industrial 690 V motor control centers. Rated insulation voltage is 800 V, so the breaker is suitable for 690 V line-to-line systems with margin. Power loss at rated current is 125.2 W maximum — factor that into enclosure ventilation if the panel is densely packed.
Internal accessories and release configuration
This variant ships with an undervoltage release (UVR) and a 1 auxiliary switch + 1 trip alarm switch (HQ configuration) factory-installed. The UVR trips the breaker when control voltage drops below a threshold — standard for emergency-stop circuits that need a held-closed contactor to drop on power loss. The auxiliary switch provides a remote status signal; the trip alarm switch signals only on a fault trip, not on manual opening. The supplied basic switch is order code 3VA14506EF320AA0 — that is the base breaker without the UVR and auxiliary switch. If you already have a 3VA1450-6EF32-0AA0 in the panel, this -0DF0 variant is a drop-in replacement with the same footprint and the added release and signaling.
Thermal derating and ambient temperature range
The breaker holds its full 500 A rating from 40 °C through 50 °C. Above that, derate linearly: 488 A at 55 °C, 476 A at 60 °C, 464 A at 65 °C, 452 A at 70 °C. If your panel ambient runs at 60 °C, you lose 24 A of headroom — still enough for a 450 A continuous load, but verify against the connected load's FLA. Operating ambient range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The storage limit governs handling and warehousing, not running conditions.