What this breaker is and what the ratings mean for fit
The Siemens 3VA2440-5HR32-0AA0 is a 3-pole IEC frame 630 molded case circuit breaker with a class M breaking capacity of Icu=55kA at 415 V AC — that is the maximum short-circuit current it can safely interrupt without damage at that voltage, which governs its suitability for high-fault installations like transformer secondaries or large motor control centers. The ETU345 LI trip unit is configured for line protection only: no overload (L) protection is active, meaning the long-time delay element is bypassed; the short-circuit protection (I) is fixed at Ii=15 x In. The continuous current rating In=400 A sets the breaker's nominal frame size, while the adjustable Ir range of 160 A to 400 A lets you match the thermal pickup to downstream cable or busbar ampacity — but since overload protection is disabled, Ir is effectively a setting for the short-time pickup, not a thermal trip threshold. The busbar connection (rear or plug-in style) suits it for direct mounting on a distribution busbar system rather than cable lugs.
Deployment context: panel integration and selectivity
As an IEC frame 630 breaker with busbar connection, the 3VA2440-5HR32-0AA0 is designed for installation in low-voltage switchgear and distribution panels where it mounts directly onto a busbar system — typical in main distribution boards (MDBs) or sub-distribution boards in industrial plants, commercial buildings, and infrastructure. The 3-pole configuration covers three-phase systems (L1, L2, L3) without a switched neutral. The class M breaking capacity (Icu=55kA @ 415V) provides headroom for selective coordination with downstream breakers rated at lower fault levels, reducing the risk of nuisance tripping on the main breaker during a downstream fault.