The Siemens SENTRON 5SJ4140-6HG40 is a 1-pole miniature circuit breaker rated 40 A at AC, designed for snap-on mounting onto a standard DIN rail. It occupies a single modular width of 18 mm, fitting tightly into a crowded panel without wasting rail space. Rated current holds at 40 A up to 40 °C ambient; at 60 °C it derates to 35.2 A — a useful curve to check if the breaker sits near heat sources inside the enclosure. The housing is halogen-free and silicon-free, which matters in environments where outgassing can contaminate contacts or optics.
Mounting and integration
Snaps onto a standard mounting rail in any position. Depth is 70 mm, so it clears most shallow enclosures; the 90 mm height and 18 mm width leave room for wiring ducts alongside. IP20 with connected conductors; IP40 in the handle range. That's fine for a dry indoor panel but not for washdown zones.
Environmental and compliance
Operating temperature range spans -40 °C to 75 °C, covering cold storage and hot panel conditions. Vibration resistance is 50 m/s² at 25 to 150 Hz and 60 m/s² at 35 Hz (4 sec) — the spectrum doesn't lie, and this breaker holds up under moderate machine vibration without nuisance trips. Sealable design, pollution degree 3, overvoltage category 3 — suitable for industrial environments where conductive dust or condensation is present.