ABB ST203M-C40 Safety Relay

ABB ST203M-C40 (also listed as S203M-C40) is a three-pole miniature circuit breaker in ABB’s System Pro M Compact family, delivering reliable overcurrent protection for three‑phase circuits. It is a 40 A device with a C‑curve tripping characteristic, and it provides a short‑circuit breaking capacity of 10 kA, with UL 1077 listing noted in multiple catalogs. This protector is designed for up to 400 V AC systems, and regionally variant part numbers within the S203M-C40 lineup include codes such as 2CDS273001R0404 and 2CDS273334R0404. In practice, it’s used in distribution panels to interrupt fault currents promptly, safeguarding conductors and downstream equipment in commercial and light industrial installations. Key specifications: 3 poles, 40 A rated current, C‑curve, 10 kA short‑circuit rating, System Pro M Compact family, UL 1077 listed. Note that voltage ratings can appear differently across regional catalogs (some US listings reference 480Y/277V while European variants commonly cite up to 400 V); always verify the exact model variant for your local supply and panel requirements.