The Siemens 5SL6240-7YA is a SENTRON miniature circuit breaker (MCB) — 2-pole, C-curve, rated 40 A with a 6 kA breaking capacity at 230 V AC per IEC/EN 60898-1. That C-curve means it trips between 5 and 10 times rated current, the standard choice for general-purpose branch circuits feeding resistive and moderate inductive loads like lighting, receptacles, and small motor starters in residential and light commercial panels.
Panel integration
Snap-on DIN rail mounting, 2-pole width (2 x 18 mm modular units). The 76 mm depth leaves clearance for standard 80 mm deep enclosures. IP20 rating with connected conductors — suitable for dry indoor panel environments. Neutral conductor is switched (1P+N design), so it fits split-phase or single-phase panels where the neutral needs overcurrent protection.
What the ratings mean for fit
The 6 kA breaking capacity at 230 V AC is the short-circuit rating per IEC/EN 60898-1 — it can safely interrupt fault currents up to 6 kA without welding or arcing over. For a 40 A C-curve, that covers most residential and light commercial service entrances where the prospective short-circuit current is below 6 kA. The C-curve (5–10x In) avoids nuisance tripping from motor inrush while still protecting branch wiring.