Insulated Metal Grounding Bushings with Dual Rated CU-AL C-Clamp Grounding Lug Zinc Die-cast 150degrees C ratedDescription Insulated Metal Grounding Bushings Insulated Metal Grounding Bushings are threaded with dual rated CU AL C clamp grounding lug. Bushings are made of Zinc die cast and are 150C rated. A larger Lay in Lug option is available that conforms to 1 0 to 250M CM max wire. Specifications Part Number Trade Size Ground Min. Wire Max Dim A Dim B Threads Inch NPNB 450 1 2" 14 4 1. 896 . 458 14 NPNB 451 3 4" 14 4 2. 109 . 482 14 NPNB 452 1" 14 4 2. 384