The Siemens SENTRON 5SJ6104-7 is a 1-pole miniature circuit breaker rated 4 A with a C-curve tripping characteristic, meaning it holds transient inrush up to 5–10× rated current before tripping magnetically — the standard choice for motor-starter and small-transformer branch circuits where the load draw is under 4 A but startup surge hits higher. Rated 240 V AC for single-phase operation and 60 V DC maximum, so it covers standard North American split-phase panels and DC control circuits up to 60 V. The AC insulation voltage is 440 V, giving headroom on 277/480 V systems if used in a line-to-neutral configuration within the 240 V per-pole limit. Snap-on DIN-rail mount, 1 width unit (18 mm), installs in any orientation.
Temperature range and environmental fit
The -40 °C minimum means no wax-thickening issues on the bimetal in freezer applications. Halogen-free and silicon-free construction — no corrosive off-gassing in a fire, and no silicone outgassing that could foul relay contacts or optical sensors in the same enclosure. Sealable (padlockable toggle) per, so a lockout/tagout procedure can physically lock the breaker off — required on some safety circuits and maintenance lockout points.
Coordination and compliance notes
Energy limiting class 3 means it restricts let-through energy well, helping with downstream device protection. Mechanical endurance rated 20 000 switching cycles — typical for a distribution MCB; not a frequent-switching device but fine for occasional manual isolation and fault clearing. Vibration resistance tested to IEC 60068-2-6 at 50 m/s² from 25 to 150 Hz and 60 m/s² from 10 to 150 Hz — holds up in panels mounted on pumps, compressors, or conveyor drives without nuisance tripping from vibration.