S203M-C20 — 20 A Curve C MCB for Branch Circuit Protection
It mounts on DIN rail and provides overcurrent and short-circuit protection for branch circuits in panelboards, sub-distribution boards, and control panels. At 20 A, that means magnetic trip between 100 A and 200 A, clearing fast enough to protect downstream wiring without nuisance tripping on normal startup. Interrupting capacity is 6 kA at 277 VAC and 10 kA at 125 VDC.
Peer Comparison — S203M-C50
The closest functional sibling is the S203M-C50, which shares the same 3-pole DIN rail form factor, Trip Curve C, and interrupting ratings (6 kA AC / 10 kA DC) but at 50 A. The S203M-C20 drops into the same panel footprint and wiring scheme — no rework needed if the panel was laid out for the C50. The only difference is the thermal-magnetic trip threshold, so the choice is purely load-current driven.
Integration — DIN Rail Panel Fit
Snap-on DIN rail mount, standard 35 mm profile. Three-pole width occupies 3 modular units (17.5 mm per pole). Spring-cage terminals accept 0.2–25 mm² copper — solid or ferruled stranded. Torque to 2.5 Nm per terminal.