The Siemens 5SJ6403-7 is a 4-pole SENTRON miniature circuit breaker rated 3 A with a C tripping characteristic, meaning it handles moderate inrush currents typical of small motor and lighting loads without nuisance tripping. The 6 kA breaking capacity (per EN 60898 and IEC 60947-2) tells you it can safely interrupt fault currents up to that level at 400 V AC — enough for most commercial and light industrial distribution boards. The 4-pole, 4-width-unit form factor (70 mm installation depth) snaps onto standard DIN rail, so it fits directly into existing SENTRON or third-party sub-distribution panels.
Integration notes
Terminals accept solid or stranded conductors from 0.75 mm² up to 25 mm², covering most branch-circuit wiring sizes. The breaker is sealable (tamper-evident seal provision) and halogen-free / silicon-free — relevant for panels in environments sensitive to outgassing, such as food processing or clean rooms. IP20 with connected conductors; mount in any position. Ambient temperature range -20 to +45 °C, with periodic excursions to +55 °C at up to 95% humidity.