The Siemens SENTRON 3VA2340-5JQ32-0BL0 is a 3-pole molded case circuit breaker rated for 400 A continuous at 40 °C, with a maximum breaking capacity of 187 kA at 240 V. It's designed for line protection in distribution panels and switchgear, and it includes an undervoltage release (UVR) plus a communication function for integration with plant monitoring systems.
Breaking capacity and thermal derating
The 187 kA at 240 V is the high-end interrupting rating — it clears massive fault currents on low-voltage secondaries. At 415 V and 440 V it still holds 121 kA, which covers most industrial 400 V-class distribution. At 690 V it drops to 7.5 kA, so if you're on a 690 V line, this breaker is for downstream sub-feeders only, not the main. Thermal derating is straightforward: 400 A from 40 °C to 50 °C, then 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. If your panel ambient runs above 50 °C, you lose 25 A per 5 °C step — plan the enclosure ventilation accordingly.
Auxiliary and release configuration
This variant ships with an undervoltage release (UVR) as the auxiliary release, plus a 2-auxiliary-switch + 1-trip-alarm + 1-electrical-alarm HQ block. That's enough for remote status feedback and undervoltage protection in one package — no separate UVR module to wire in. The basic switch version is 3VA2340-5JQ32-0AA0; the -0BL0 suffix adds the communication function. If you need Modbus or PROFIBUS connectivity, this is the order code that carries it.
Panel fit and environment
Dimensions are 248 mm high, 138 mm wide, 110 mm deep — a standard SENTRON 3VA frame size that drops into existing Siemens panel layouts without re-drilling. Operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C. Max power loss is 98.5 W, so factor that into the enclosure thermal budget.