ABB ST201M-Z4 Two-Channel Safety Relay Module

ABB ST201M-Z4 is a single-pole miniature circuit breaker (MCCB) with a Z-curve trip characteristic and a nominal current rating of 4 A. It is designed for 480Y/277 V AC circuits and provides a maximum interrupting capacity of 10 kA at this voltage. Listed to UL 1077 as a supplementary protector, the ST201M-Z4 is intended for branch-circuit protection in electrical distribution panels and control enclosures, safeguarding wiring and devices from overloads and short circuits. The 1P design protects a single live conductor, making it suitable for compact machine control and panel wiring where precise overcurrent protection is required without affecting other circuits. The Z-curve characteristic ensures selective tripping in systems with multiple protective devices, helping to isolate faults while maintaining operation on unaffected paths. Authorized ABB distributors and electronics catalogs commonly stock the ST201M-Z4, including Proax, Rexel, and Mouser, which confirms its status as a standard, widely available component for industrial installations.