The Siemens SENTRON 3VA2440-6KQ32-0AA0 is a 3-pole molded case circuit breaker rated for 400 A continuous current (Iu) with an ETU860 electronic trip unit. This is a line-protection version, meaning it is configured for feeder and main breaker duty rather than motor or generator protection. The 242 kA breaking capacity at 240 V (187 kA at 415 V, 85 kA at 440 V, 55 kA at 500 V, 9 kA at 690 V) covers high-fault installations where the available short-circuit current is substantial — common in industrial distribution switchboards and large panelboard mains.
Thermal derating and continuous current
The 400 A rating holds from 40 °C through 50 °C ambient. Above that, derating is linear: 388 A at 55 °C, 380 A at 60 °C, 368 A at 65 °C, 352 A at 70 °C. For a panel builder, this means the breaker can be installed in a warm enclosure without sacrificing full capacity up to 50 °C — common in enclosed switchgear. At 70 °C the part still delivers 352 A, which is 88% of the nameplate rating.
Trip unit and protection functions
The ETU860 electronic trip unit supports adjustable response time (tr max. 25) and includes ground fault monitoring via summation current formation on the L-conductor. Communication function is present, which allows integration into a power monitoring or SCADA system — useful for a facility engineer tracking trip events or doing remote coordination studies. The breaker also carries an 'Other Measurement Function' flag, indicating it can report electrical parameters beyond basic protection.
Mounting and panel fit
Dimensions are 248 mm height, 138 mm width, 110 mm depth. The width of 138 mm is the standard 3-pole MCCB footprint for this current class — it will drop into a panel cutout designed for a SENTRON 3VA2 frame without modification. The 110 mm depth leaves clearance for rear-mounted bus bars or cable lugs in a typical 600 mm deep enclosure. IP40 on the front means it is protected against tools and small wires, but not against washdown — standard for indoor switchgear.