Siemens 5SP3740-3 — SENTRON 1-pole MCB, Characteristic E, 25 kA
The Siemens 5SP3740-3 is a 1-pole SENTRON miniature circuit breaker with tripping characteristic E, rated for 230 V AC (50 Hz) and a breaking capacity of 25 kA per EN 60898. The 25 kA interrupting rating means this MCB can safely clear a fault current up to that level without welding contacts or rupturing the case — critical for high-fault installations near transformers or in industrial sub-distribution boards where prospective short-circuit current is substantial.
Physical Fit & Environmental Ratings
Height 128 mm, depth 76.3 mm — fits standard 1.5-module DIN-rail cutouts. The depth dimension is the enclosure depth behind the panel face; verify clearance to the back wall or wiring duct. IP40 with conductors connected — suitable for dry indoor enclosures; not rated for washdown or outdoor exposure. Ambient range -40 to 70 °C covers extreme cold storage or hot substation conditions. Shock rated 30 g, 11 ms duration; vibration 2 g, 5–150 Hz per IEC 60068-2-6 — survives transport and moderate machine vibration. Terminals accept solid or stranded copper up to 50 mm², minimum 2.5 mm² — saddle terminals with box-terminal infeed. Pollution degree 3 and overvoltage category IV confirm suitability for main distribution panels where conducted transients are severe. Sealable via integrated locking slide for lock, wire seal, or cable tie.