The Schneider Electric G12FASB2 is an interphase barrier for the GoPact MCCB 125 range — a molded-case circuit breaker accessory that fits between pole connections to maintain phase-to-phase insulation clearance. It ships as a set of two parts, each 54 mm wide, 43 mm tall, and 1.4 mm thick. This is a spare-part category item, not a standalone breaker; it mounts upstream or downstream of the breaker body, depending on the wiring layout.
Designed for the GoPact MCCB 125 frame — the 54 mm width matches the pole spacing on 3P and 4P configurations. The 1.4 mm thickness is a formed insulation sheet, not a structural bracket; it slides between the phase barriers during assembly. Panel builders should confirm the barrier orientation relative to the line and load side terminals; the part is marked for upstream or downstream placement but not polarity-sensitive.