MCCB for high-fault panels
The Siemens SENTRON 3VA2450-7JQ42-0AA0 is a 4-pole molded case circuit breaker rated 500 A continuous at 40 °C, with an ETU560 electronic trip unit. This is the line protection version — no undervoltage release, no voltage trigger, but it does carry a communication function for integration into a monitored distribution system. The interrupting ratings are the headline: 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 9 kA at 690 V. Those numbers mean it can safely clear a fault at the main service entrance or a high-capacity sub-distribution board without cascading upstream — the 330 kA figure at 240 V is typical for a transformer secondary or a large UPS output. The 4-pole construction handles three-phase plus neutral, so it fits a TN-S or TN-C-S system where the neutral needs protection.
Thermal derating and enclosure fit
The 500 A rating holds flat from 40 °C through 50 °C, then derates to 477 A at 55 °C, 455 A at 60 °C, 432 A at 65 °C, and 410 A at 70 °C. In a sealed panel with no forced ventilation, expect to apply that curve. The footprint is 248 mm high by 184 mm wide by 110 mm deep — a standard MCCB envelope for this frame class. Front IP40 means the breaker face is protected against solid objects over 1 mm, but the terminals and bus connections are not sealed; install in a panel with at least IP40 overall. Maximum power loss is 99 W, which factors into the enclosure thermal budget.
Ground-fault and compliance details
The ground-fault monitoring uses summation current formation on the L + N conductors — a residual-current approach that detects imbalance between phase and neutral without a separate toroid. Rated insulation voltage Ui is 800 V, so it can be applied in 690 V systems with margin. The reference code per IEC 81346-2 is Q (switching device). Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.