Short-circuit capacity and trip curve
The 5SY4303-5: Its tripping characteristic A means it trips on overloads faster than a B-curve — the magnetic release threshold is around 2-3× In, so it catches short-duration overcurrents on sensitive loads like semiconductor circuits or long control cable runs before they damage the downstream gear. For UL 1077 applications it's rated 5 kA.
DC rating and environmental range
Rated for DC circuits up to 60 V (max 72 V operating) with a DC breaking capacity of 15 kA per IEC 60947-2 — that covers 48 VDC control power and 60 VDC solar-combiner box circuits, but not 125 VDC railway or telecom plants. The poles are not series-connected for higher DC voltage; this is a straight 3-pole block. That -40 °C floor makes it usable in unheated warehouse or cold-store environments without condensation concerns.
Width is 54 mm (3 modular units), depth 76 mm, height 90 mm. Snap-on quick-assembly system to DIN rail — any mounting position. Sealable with a lead seal or sticker for revenue-meter or safety-circuit applications where tamper evidence is required.
Current production — no EOL notice on record. The 5SY4 series is the standard SENTRON MCB line; the 5SY4303-5 is the 3-pole A-curve variant at 400 VAC.