Use the Bridgeport 389-40 3-1/2-Inch Malleable Iron Insulated Grounding Bushing to terminate service conduit to a cabinet with a locknut. Featuring a plastic metaliner that prevents damage to wire insulation and a 6 to 250 MCM lug for bonding a jumper to a neutral busbar. Temperature rated to 150 degrees Celsius, this bushing is 1-inch long with diameters of 3-3/8 inches and 4-5/16 inches, and is solidly built to meet construction and general industry OSHA-recognized, NRTL-listed electrical standards