The Siemens 5SL5818-7 is a 2-pole miniature circuit breaker rated 15 A with a C characteristic, designed for 110 V DC circuits and a 6 kA breaking capacity. The C curve means it trips between 5 and 10 times rated current — standard for motor and lighting loads where inrush isn't extreme. At 1 MW (18 mm) wide per pole, it fits the standard DIN-rail enclosure footprint without stealing space from adjacent devices.
DC circuit protection — what the 110 V rating means on the line
This breaker is rated for 110 V DC, not the usual 230/400 V AC you see on most 5SL5 units. DC arcs are harder to extinguish than AC — they don't have a natural zero-crossing — so the 6 kA interrupting rating at 110 V DC is the real number that governs whether this part clears a fault on a DC bus or battery-backed control circuit. If your BOM calls for DC-side protection on a 48 V or 110 V nominal system, the C characteristic gives you the headroom for capacitor inrush without nuisance trips.