1-pole D-curve MCB, 2 A, 10 kA
The Siemens 5SL4102-8 is a SENTRON miniature circuit breaker — 1 pole, D characteristic, rated 2 A at 230/400 V AC. Rated voltage is 250 V single-phase, 440 V multi-phase. The 2 A rating at 30 °C derates to 1.92 A at 40 °C and 1.79 A at 55 °C — relevant if the breaker sits in a crowded enclosure where ambient climbs. DC rating tops at 72 V. Mounting position is unrestricted; the unit occupies 1 modular width (18 mm) on DIN rail.
D-curve selectivity and coordination
The D characteristic is the key selection parameter here. For a 2 A MCB, the magnetic trip threshold sits at 20–40 A instantaneous. That means it ignores the cold inrush of a small control transformer or a 0.75 kW motor start — the kind of load that would trip a C-curve breaker of the same amp rating. Energy limitation class 3 means it lets through less let-through energy (I²t) than class 1 or 2 breakers, which helps downstream semiconductor protection.
IP20 with connected conductors; not rated for washdown.