What the ratings mean for your panel
The Siemens 5SL3140-6 is a 1-pole miniature circuit breaker from the SENTRON 5SL3 series, rated 40 A with a B-curve tripping characteristic. The B-curve means it trips at 3–5× rated current — designed for resistive and general-purpose loads in residential and light commercial panels, not for high-inrush motor starts. The 4.5 kA breaking capacity per EN 60898 and IEC 60947-2 tells you it can safely interrupt fault currents up to that level without upstream damage, which covers most domestic and infrastructure distribution boards. Single-pole (1P) construction with 18 mm width per DIN rail module means it occupies one standard unit in the enclosure. The 76 mm depth and 70 mm installation depth fit standard distribution boards without protruding past the cover. Terminal capacity accepts 0.75 to 25 mm² solid or stranded copper — enough for 40 A feed conductors without needing a reducer.
Panel integration and mounting
Snap-on DIN rail mounting, any position. The 18 mm width (1 width unit) and 70 mm installation depth fit existing distribution boards without panel rework. Screw-type terminals with 2.5 to 3 N·m tightening torque. Sealable design (yes) allows the installer to lock the toggle position after commissioning — useful for tamper-proofing in shared or public-access panels.
Environmental and compliance notes
Rated for ambient temperature -25 to +45 °C, with periodic exposure to +55 °C and up to 95% humidity. Storage range -40 to +75 °C. Halogen-free and silicon-free construction — relevant for clean-room or sensitive electronic environments where outgassing matters. Overvoltage category 3, energy limiting class 3. Rated AC voltage 400 V (single-phase), maximum 440 V multi-phase. DC rated maximum 60 V — not a primary DC breaker, but can handle low-voltage DC circuits within that limit.