400 A MCCB with ETU560 — what the ratings mean for your panel
The Siemens SENTRON 3VA2440-6JQ42-0AA0 is a 4-pole molded case circuit breaker rated for 400 A continuous current (Iu) at 40 °C, with the ETU560 electronic trip unit managing the overcurrent release. That 400 A holds flat through 50 °C — no derating needed up to that point — then drops to 388 A at 55 °C, 380 A at 60 °C, 368 A at 65 °C, and 352 A at 70 °C, so if your panel ambient runs hot you size off the 55 °C or 60 °C column, not the 40 °C sticker. Breaking capacity is where this frame earns its keep: 242 kA at 240 V, 187 kA at 415 V, 85 kA at 440 V, 55 kA at 500 V, and 9 kA at 690 V. That 187 kA at 415 V tells you it handles high-fault scenarios common in industrial distribution without needing a current-limiting fuse upstream — a real space saver in a packed enclosure. The ETU560 is a communicating trip unit — the breaker carries a communication function, so it can talk to a higher-level control system for power monitoring and selective coordination. The N-conductor protection is adjustable (OFF, 20 % to 130 %), and ground fault monitoring uses summation current formation on L + N. That makes it suited for TN or TT systems where you want both phase and neutral protection in one package.
Panel fit — 184 mm wide, 248 mm tall, 110 mm deep
The 3VA2440-6JQ42-0AA0 measures 184 mm wide by 248 mm tall by 110 mm deep. The 184 mm width fits a 4-pole frame in a standard SENTRON footprint — 7.2 inches of DIN-rail space, and the 110 mm depth (4.3 in) keeps the breaker from protruding past the gland plate. Front IP40 protection suits a clean indoor panel.