DC-rated miniature circuit breaker for 440 V strings
The Siemens 5SL5202-7RC is a 2-pole miniature circuit breaker from the SENTRON 5SL series, rated for DC circuits up to 440 V with a 10 kA breaking capacity and a C-curve trip characteristic. This is a DC-specific MCB — the 440 V DC maximum rating means it can handle series strings common in solar combiner boxes, UPS battery banks, and DC bus distribution, where standard AC-rated MCBs would fail to interrupt a DC arc. The 2-pole design switches both lines simultaneously, which is necessary for ungrounded DC systems to ensure full isolation on a fault. The IP20 rating applies with conductors connected, so it's intended for protected panel or enclosure installation, not open wet locations.
The 90 mm height is standard for SENTRON 5SL breakers — drops into existing 5SL panel layouts without re-spacing. Mounts in any position, which simplifies layout in tight enclosures where vertical rail orientation is needed.