An isolator fitting for an opening in a metallic rib of an aircraft wing. The isolator fitting has first isolator mountable to the rib to position a first isolator opening in alignment with the opening of the rib. A second isolator is mountable to the rib and has a nut housing segment defining a second isolator opening to be positioned in alignment with the opening of the rib. A conduit extends between a first end and a second end, and a nut is mountable about an outer surface of the conduit to abut against the first isolator and mount the conduit thereto. The conduit is positionable to extend through the opening of the rib and through the first and second isolator openings to position the nut within the nut housing segment of the second isolator such that the nut housing segment is positioned between the nut and the rib.