The Siemens SENTRON 5SP3725-2KK01 is a 1-pole miniature circuit breaker rated 25 A with an E tripping characteristic and a 25 kA breaking capacity per EN 60898. It mounts via busbar fastening and occupies 1.5 modular width units on the DIN rail.
Key ratings — what they mean for the panel
Rated 25 A at 30 °C, this breaker handles the full 25 A in a typical panel environment. At elevated temperatures, it derates linearly: 23.75 A at 40 °C, 22.5 A at 50 °C, and 21.875 A at 55 °C — important to check if the breaker sits near other heat sources in a crowded enclosure. The 25 kA breaking capacity at 230 V AC (per EN 60898) means it can safely interrupt a fault current up to 25,000 A without welding contacts or exploding. Insulation voltage is rated 690 V, surge voltage resistance is 6 kV, and overvoltage category is IV — this breaker is built for the main distribution point where the utility feed comes in, not just sub-panels. Pollution degree 3 means it tolerates conductive dust and occasional condensation, which is typical for meter cabinets and outdoor-rated enclosures.
Integration into the meter panel
Busbar-mounted, 1.5 MW wide — that's 27 mm on a standard DIN rail. Accepts solid or stranded copper up to 50 mm², minimum 2.5 mm². The enclosure depth is 76.3 mm; overall depth including terminals is 89.5 mm. Height is 151.3 mm. IP40 with conductors connected. Sealable with a locking slide, wire seal, cable ties, or Antilux — required by many utility metering codes to prevent tampering. Infeed is via box terminal at the bottom; outgoing feeder uses a spring-loaded terminal.