The ABB S201-Z1 is a 1-pole miniature circuit breaker rated 1 A with Trip Curve Z, designed for DIN-rail mounting in distribution panels and control cabinets. Rated 277 VAC with a 6 kA interrupting capacity, it protects semiconductor circuits and sensitive electronic loads.
Trip Curve Z — what it means for the circuit
Curve Z is the tightest magnetic-trip band in the S200 family, operating between 2× and 3× rated current (2–3 A for this 1 A unit). This makes it the correct choice for protecting control transformers, PLC power supplies, and analog I/O loops where a standard Curve C would allow fault current to persist long enough to cook the load. The 6 kA interrupting rating at 277 VAC is sufficient for most commercial and light industrial panelboards where the available fault current stays under that threshold.