Square D PQ4203 Fusible Bus Plug Horizontal Unit

Square D PQ4203 fusible bus plug for I-Line busway is a 30 A, four-pole plug-in unit that provides fused protection and a grounded connection for Square D bus duct systems. The PQ4203G variant is rated for up to 240 V AC, with common configurations supporting 120/208/240 V, and houses three fuses plus an integral ground bus within an FS-frame, NEMA 1 enclosure for indoor installations. As a plug-in bus plug, it mates with compatible I-Line busway sections to feed downstream equipment such as panels or switches, delivering localized protection and straightforward fuse replacement in commercial or light industrial environments. The four-conductor arrangement supports three current paths plus a ground, aligning with a 30 A rating for compact feeders and preserving the busway’s modular, plug-in design. Typical applications include providing a fusible feed to branch circuits in power distribution layouts where a fusible protection device is preferred at the point of use along an I-Line bus run.