C-curve 1 A MCB for 400 V AC railway and industrial panels
The Siemens SENTRON 5SY4201-7CC11 is a 2-pole miniature circuit breaker with a C-curve tripping characteristic, rated at 1 A AC and 400 V. Its 10 kA breaking capacity per EN 60898 means it safely interrupts short-circuit faults up to that level on a 400 V line without upstream device coordination issues — sized for sub-distribution boards in mechanical engineering and railway applications where the fault current is known and moderate. The C-curve (5–10× In magnetic trip) suits moderate inrush loads like small contactor coils, lighting banks, or control transformers where a B-curve would nuisance-trip on start-up but a D-curve is unnecessary. At 1 A, this is a control-circuit or instrumentation feeder breaker, not a main distribution device.
DIN-rail footprint and terminal handling
Mounts on a standard DIN rail via the quick assembly system; 36 mm width (2 width units) and 70 mm installation depth leave room for adjacent breakers in a crowded enclosure. Accepts solid or stranded copper from 0.75 mm² up to 35 mm² at the screw-type terminals, tightened to 2.5–3.5 N·m — enough for a single 6 mm² feed or a loop-through of two 4 mm² conductors. The combined terminal (top and bottom) accepts a busbar or fork lug without adapter plates. IP20 with connected conductors — protected against finger contact once wired, but not against dripping water. This is a dry indoor panel breaker, not a washdown enclosure device. The sealable option (padlockable toggle) allows lockout/tagout on the breaker handle without an external lockout hasp.