The Siemens SENTRON 5SL6140-6YA is a 1-pole miniature circuit breaker with a B tripping characteristic, rated 40 A at 30 °C and 400 V AC. It interrupts fault currents up to 6 kA per EN 60898, which covers the standard domestic and light commercial fault level in most 230/400 V networks. The B curve means it trips between 3 and 5 times rated current — suited for resistive and general-purpose loads where inrush is modest, not for motor circuits that draw a higher starting surge.
What the ratings mean for fit
The 40 A rating at 30 °C is the headline figure, but the derating curve matters in a warm panel: at 40 °C ambient the breaker is rated 0.96 A (a clear data anomaly — likely a misprint for a different variant; the 45 °C figure of 37.2 A is more plausible for this class). In practice, size the continuous load at no more than 32 A in a 40 °C enclosure to avoid nuisance tripping. The 6 kA interrupting rating per EN 60898 is the standard for residential and light commercial distribution boards; it safely clears a bolted fault up to that level without rupturing. The B curve (3–5× In) gives fast magnetic trip for short circuits while passing normal inrush from lighting and control transformers.
Where it goes
Occupies 1 modular width unit (18 mm). Mounting position is any. IP20 rating applies with distribution board cover fitted.