What the ratings mean for fit
The Siemens SENTRON 3VA1463-7FF42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated at 315 A continuous, with a TM240 thermal-magnetic overcurrent release designed for line protection. The 315 A rating is the maximum and minimum — this is a fixed-frame breaker, not adjustable down. That 440 kA breaking capacity at 240 V tells you it can interrupt very high fault currents at low voltage, which matters for large transformer secondaries or busway feeds where the available fault current is extreme. At 415 V and 440 V it still clears 242 kA, and at 690 V it holds 17 kA — so the SCCR headroom depends heavily on the system voltage you're working with. The TM240 release is a fixed thermal-magnetic trip unit — no electronic adjustments, no communication module, no ground-fault monitoring. That keeps the part simple and reliable for straightforward feeder protection, but if you need adjustable long-time or short-time pickup curves, this isn't the variant. The 192.9 W maximum power loss means the breaker dissipates heat into the enclosure; factor that into your panel thermal budget, especially when mounting multiple breakers side by side.
Thermal derating and ambient conditions
The breaker carries its full 630 A rating from 40 °C through 50 °C ambient — that's the thermal-magnetic trip curve's reference point. Above 50 °C it derates linearly: 618 A at 55 °C, 607 A at 60 °C, 595 A at 65 °C, and 583 A at 70 °C. If your panel ambient runs hot, the actual continuous current capability drops; size the upstream conductor and downstream load accordingly. Operating range is -25 °C to 70 °C, storage from -40 °C to 80 °C. The IP40 front protection means it's fine in a clean indoor panel but not for washdown or outdoor exposure without an additional enclosure.
Physical fit and panel integration
Dimensions are 248 mm high, 184 mm wide, 110 mm deep. That 184 mm width across four poles is standard for this frame size — it occupies the same panel footprint as other 3VA 4-pole breakers in the 315 A class. The breaker mounts with screw terminals; no DIN-rail clip on this frame size. Verify the busbar or cable lug pattern against your existing panel layout before ordering.