The Schneider Electric A9XPH218 is an Acti9-series comb busbar — a cuttable, insulated distribution bar that feeds 18 modules of DIN-rail mounted devices in a 1L+N (single-phase plus neutral) arrangement. It's the backbone bar for a row of miniature circuit breakers or RCBOs in a residential or light commercial panel. The 18 mm connection pitch matches standard single-pole MCB spacing, and the 18-module length covers a full row in a compact enclosure. Built to EN/IEC 61439-1 (low-voltage switchgear and controlgear assemblies) and IEC 60947-7-1 (pollution degree 3), it's designed for the dirtier environment inside a panel where conductive dust can settle. The IP20 rating with end-pieces and tooth covers means it's touch-safe once installed but not for wet or washdown locations.
The 18-module length (324 mm wide) and 18 mm pitch mean it fits exactly across 18 single-pole ways. The cuttable design lets you trim it to a shorter row if needed. Mounts horizontally on tunnel-type terminals or double terminals, top or bottom of the device row. The tooth-type connector engages with the MCB's terminal clamp. Fire resistance tested to 960 °C for 30 seconds per IEC 60695-2-1 — that's the glow-wire test for parts that stay live in a fault condition. It won't propagate a fire inside the panel under a short-circuit event.