Breaking capacity and selectivity planning
The Siemens 3VM1150-4EE46-0AA2 is a 4-pole circuit breaker on the IEC frame 160 platform, rated for a breaking capacity class S with Icu=36kA at 415V. That 36kA figure is the ultimate short-circuit breaking capacity — the breaker can safely interrupt a fault up to that level once, after which it must be replaced. For selective coordination downstream, the short-circuit release is fixed at Ii=10 x In (500A), which helps keep upstream devices from tripping on a downstream fault, provided the upstream breaker's instantaneous threshold is set higher.
Overload and short-circuit protection settings
The TM220 thermal-magnetic trip unit gives an adjustable overload protection band Ir=35A...50A, letting you match the breaker to the actual continuous load current within that window. The magnetic short-circuit protection is fixed at Ii=10 x In (500A). The N conductor is unprotected — the neutral pole is switched but not monitored for overcurrent. Terminal connection type is assumed for panel wiring; verify lug range against your cable cross-section during commissioning.