What the ratings mean for fit
The Siemens SENTRON 5SL4414-8 is a 4-pole miniature circuit breaker with a D tripping characteristic, rated 0.3 A at 400 V AC. The D curve means it tolerates high inrush currents — typically 10–20× rated current for short durations — making it the right choice for motor starter circuits, transformer primaries, or capacitive loads where a B or C curve would nuisance-trip on startup. The 10 kA breaking capacity is certified under both EN 60898 (household/residential standard) and IEC 60947-2 (industrial standard), so it can safely interrupt fault currents up to 10 kA without upstream damage. That dual rating covers installations from residential distribution boards to industrial panel feeders.
Thermal derating and environmental limits
The 0.3 A rating holds at 30 °C ambient; at 40 °C it derates to 0.28 A, and at 55 °C to 0.26 A. If the panel runs warm — say, adjacent to a drive or transformer — use the 55 °C figure for sizing. The breaker is rated for any mounting position, which simplifies layout in crowded enclosures. Pollution degree 2 (non-conductive dust, occasional condensation) covers most clean industrial and residential environments. Overvoltage category III means it's rated for fixed installations downstream of the main distribution board.
Panel integration and compliance
The breaker occupies 4 modular width units (72 mm wide) on a DIN rail, with a depth of 76 mm and an installation depth of 70 mm. It's sealable, halogen-free, silicon-free, and provides touch protection on the terminals. IP20 rating applies with connected conductors — standard for enclosed distribution boards. Compliance documentation (RoHS, REACH, UL, IEC) is available with the shipment; the part is certified under both EN 60898 and IEC 60947-2, so it meets the documentation requirements for most industrial and infrastructure projects.