The Siemens 5SL3540-7 is a SENTRON 5SL3 miniature circuit breaker rated 40 A with a C tripping characteristic, 2-pole (1P+N) configuration, and a 4.5 kA breaking capacity per both EN 60898 and IEC 60947-2. Rated 230 V AC supply voltage, with a maximum DC rating of 60 V.
Terminal accepts solid or stranded conductors from 0.75 to 25 mm²; tightening torque is 2.5 to 3 N·m on the screw terminals. IP20 with connected conductors — that's touch-protected terminals but not sealed against dust ingress, so it lives inside a distribution board, not in a washdown zone.
The 40 A C-curve is the headline fit check: if your circuit is protecting a 40 A resistive or moderate-inrush load at 230 V AC single-phase, this breaker matches. The 1P+N pole configuration switches both phase and neutral — the neutral pole is switched but not protected, which is standard for single-phase final circuits in many European distribution boards. Energy limiting class 3 means it restricts let-through energy well, reducing stress on downstream equipment during a fault.