The Siemens 5SJ4208-7HG41 is a 2-pole SENTRON miniature circuit breaker from the 5SJ4 series, designed for branch-circuit protection in industrial control panels. It carries a C tripping characteristic — the standard choice for moderate inrush loads like small motors, contactor coils, and control transformers — with a rated breaking capacity of 10 kA per EN 60898 and 15 kA per IEC 60947-2 at 400 V AC.
Electrical ratings and what they mean for the BOM
Rated insulation voltage (Ui) is 440 V AC, with an overvoltage category of 3 and pollution degree 3 — this means it's rated for fixed installations in industrial environments where transient overvoltages are expected. The DC rating of 60 V covers common control-circuit voltages. The C-curve trips at 5 to 10 times rated current, so it holds through the inrush of a contactor or small motor starter but clears a hard fault fast. The 10 kA (EN 60898) and 15 kA (IEC 60947-2) ratings give the panel designer headroom for selectivity studies; the higher IEC number is the one to use for industrial coordination.
Environmental and compliance notes
Rated for ambient temperatures from -40 °C to 75 °C, with up to 95% humidity. The housing is halogen-free and silicon-free, which matters for panels in clean-room or semiconductor-adjacent zones where outgassing can contaminate optics or contacts. Vibration resistance is specified at 50 m/s² over 25 to 150 Hz and 60 m/s² at 35 Hz for 4 seconds — sufficient for mounting on machine frames or near rotating equipment. The breaker is sealable (provision for a lead seal or lockout tag) and carries IP20 protection with connected conductors, IP40 in the handle area.