Siemens 5SY7540-7 SENTRON MCB — 40 A, C-Curve, 2-Pole 1P+N
The Siemens 5SY7540-7 is a 2-pole miniature circuit breaker from the SENTRON 5SY7 series, configured as 1P+N with a 40 A rated current and C tripping characteristic. It protects branch circuits against overload and short-circuit in industrial control panels, distribution boards, and machinery — the C-curve (5–10× In) handles moderate inrush from motor starters, contactor coils, and small transformers without nuisance tripping. Rated 230 V AC, with a breaking capacity of 15 kA per EN 60898 and 20 kA per IEC 60947-2, it covers most European industrial installations where fault levels stay under those thresholds. Mounts on DIN rail via the quick-assembly system, occupying 2 width units (36 mm). Installation depth is 70 mm; overall depth is 76 mm. Any mounting position is permitted, and the enclosure carries IP20 protection with conductors connected — standard for enclosed distribution panels.
Breaking Capacity and Selectivity
The 5SY7540-7 is rated 15 kA at 230 V AC per EN 60898, and 20 kA per IEC 60947-2. For DC circuits, it breaks 15 kA at 72 V DC per IEC 60947-2. Under UL 1077 and CSA C22.2 No. 235, it carries a 5 kA rating. These figures determine where the breaker sits in a selective coordination study — upstream devices must have a higher or equal kA rating to clear faults before this MCB reaches its limit. Pollution degree 3 and overvoltage category III suit it for fixed industrial installations where transient overvoltages are expected.
Sourcing and Availability
The 5SY7540-7 is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time. For a BOM line that needs this exact order code, submit an RFQ — the supply posture is active, and the part is specified into new and replacement industrial panels.