The Siemens 5SL6240-6 is a 2-pole SENTRON miniature circuit breaker from the 5SL6 series, rated 40 A with a B tripping characteristic and a breaking capacity of 6 kA per EN 60898 at 400 V AC. This is the standard MCB for residential and infrastructure branch-circuit protection — think final subcircuits feeding general-purpose socket outlets or lighting in a panelboard. The B-curve (3–5× In) means it trips fast on moderate overloads, so it pairs with resistive and light inductive loads where inrush isn't extreme.
The B-curve (3–5× In) determines the magnetic trip threshold: between 120 A and 200 A instantaneous. That's appropriate for general-purpose circuits feeding multiple outlets or lighting — not for motor circuits where higher inrush (C or D curve) would be needed to avoid nuisance trips. In a domestic or light commercial distribution board this is usually sufficient; if your fault level exceeds 6 kA at the point of installation, you'd need a higher-rated device upstream or a current-limiting backup fuse. The 2-pole configuration (switching both line and neutral, though neutral is not switched separately per) fits single-phase or split-phase circuits where both conductors need overcurrent protection. Rated voltage is 400 V AC between phases, with a maximum of 440 V in multi-phase operation.
Deployment context
Terminal capacity accepts 0.75 mm² to 25 mm² conductors, so it handles both final-circuit wiring and larger feeder tails.