The ABB S202-D40 is a 2-pole miniature circuit breaker with a D trip curve, rated 40 A at 277 VAC and a 6 kA interrupting capacity. That 40 A rating sits at the upper end of the S200 series, sized for a 7.5–10 kW motor depending on line voltage and duty. The 2-pole format breaks both line and neutral on a 277 VAC single-phase circuit (common in 480Y/277 V wye systems) or two phases of a delta supply. No neutral pole — it's a two-pole overcurrent device, not a switched neutral.
Panel fit: S202-D40 vs. S202M-C25
The S202M-C25 (25 A, C curve) shares the same 2-pole DIN-rail footprint, 277 VAC rating, and 6 kA interrupting capacity. The deciding difference is the trip curve and amp rating: the S202-D40 handles a 40 A motor or transformer load where the C25 would trip on inrush; the C25 is the right choice for resistive or low-inrush circuits at 25 A. Both mount identically — no rework needed to swap them in the same enclosure slot.
Integration note
Snaps onto standard DIN rail; the S200 series uses a spring-loaded latch that releases with a flathead screwdriver. Terminal torque spec is 2–2.5 Nm for the cage clamps, accepting 1–25 mm² conductor. Leave at least 10 mm between adjacent breakers for heat dissipation at 40 A continuous.