Curve C means the magnetic trip threshold sits at 5 to 10 times the rated current — 100 to 200 A for this 20 A breaker. Interrupting rating is 6 kA at 277 VAC and 10 kA at 60 VDC. The 6 kA AC figure is the standard for residential and light commercial panelboards in most IEC markets; the 10 kA DC rating covers battery-backed control circuits and DC bus distribution in the same panel.
How it compares to the 40 A sibling
The S201M-C40 shares the same 1-pole DIN-rail footprint, same 277 VAC / 60 VDC voltage ceiling, and same 6 kA interrupting rating. The only difference is the current rating — 40 A instead of 20 A.
Panel integration note
The 1-pole width (roughly 17.5 mm) means it occupies one module position in a standard distribution board. Busbar comb can be fed through the top or bottom terminals; the S200M series accepts pin or fork busbar lugs without adapters.