S203-K40, 3-pole miniature circuit breaker, 40 A, Trip Curve K, 277 VAC, 10 kA interrupting capacity, DIN rail mount.
| Parameter | Value |
|---|---|
| Number of poles | 3 |
| Parameter | Value |
|---|---|
| Voltage (AC) | 277 |
| Current (A) | 40 |
| Parameter | Value |
|---|---|
| Interrupting rating (AC) | 10 kA |
| Parameter | Value |
|---|---|
| Mounting type | DIN Rail |
| Parameter | Value |
|---|---|
| Type | Trip Curve K |
The S203-K40 is a 3-pole miniature circuit breaker rated 40 A with a Trip Curve K characteristic, meaning it trips magnetically at 8–12x rated current — designed for loads with moderate inrush like motors, transformers, and solenoid valves where a standard Curve C might nuisance-trip on startup but Curve D would be too slow for conductor protection. Rated 277 VAC phase-to-neutral. Interrupting capacity of 10 kA at 277 VAC. Mounts on standard DIN rail.
Physically yes — both mount on the same DIN rail and share the same 3-pole footprint. But the K40 is 40 A vs 10 A, so the downstream conductor and load must be rated for 40 A. The trip curve is also different (K vs D), so coordination with upstream devices may change.