Panel Fit and Peer Comparison
The S201P-C16: The S201PR-K20 is a physically similar peer — same System pro M compact family, same 1-pole DIN-rail footprint. The difference is the curve: K-curve on the K20 (10-14x In) versus C-curve on this C16 (5-10x In). If your panel was specced around the S201PR-K20, the C16 will clip into the same rail and busbar, but the trip curve is different — verify selectivity and coordination with downstream loads before swapping. The S204M-C16 is a 4-pole variant of the same C16 rating; the SH203T-C32 is a 3-pole T-curve device at a higher current — different footprint and application.