What it is and what the D-curve means
The S201M-D16 is a thermal-magnetic miniature circuit breaker (MCB) from ABB's S200 series, rated 16 A with a D tripping characteristic. The D-curve means the magnetic trip is set to 10-20 times rated current — designed for loads with high inrush, like small motors, transformers, or capacitive banks. The thermal element handles overloads; the magnetic element clears short-circuits. It mounts on a standard DIN rail, so it slots into any distribution board or control panel without modification.