An assembly installable in a hole of a workpiece (584, 2236), the assembly comprising: a cage assembly (422, 2249) including an abutment portion (540, 570); a mounting plate (430, 460, 2250) including a metallic expandable portion, the metallic expandable portion dimensioned to fit in the hole (582, 2410) of the workpiece from a first surface of the workpiece and to form an interference fit with the workpiece, the cage assembly operably being seated against the first surface of the workpiece and the abutment portion operably being sandwiched between the mounting plate and the workpiece; and a sealed dome nut assembly including a cap retainer coupled to the cage assembly and including a retainer body and a retainer sealing member, the retainer body defining a retainer passage, the retainer sealing member compressed against the mounting plate, a dome cap having a closed end, a cap base, and a cap sealing member, the cap base positioned within the cap retainer such that the cap sealing member sealingly engages a portion of the cap retainer surrounding the dome cap, a nut element having a first end, a second end, and a nut body, the nut body defining a passage for receiving a fastener extending through the metallic expandable portion of the cage assembly and the second end of the nut element. a cage assembly (422, 2249) including an abutment portion (540, 570); a mounting plate (430, 460, 2250) including a metallic expandable portion, the metallic expandable portion dimensioned to fit in the hole (582, 2410) of the workpiece from a first surface of the workpiece and to form an interference fit with the workpiece, the cage assembly operably being seated against the first surface of the workpiece and the abutment portion operably being sandwiched between the mounting plate and the workpiece; and a sealed dome nut assembly including a cap retainer coupled to the cage assembly and including a retainer body and a retainer sealing member, the retainer body defining a retainer passage, the retainer sealing member compressed against the mounting plate, a dome cap having a closed end, a cap base, and a cap sealing member, the cap base positioned within the cap retainer such that the cap sealing member sealingly engages a portion of the cap retainer surrounding the dome cap, a nut element having a first end, a second end, and a nut body, the nut body defining a passage for receiving a fastener extending through the metallic expandable portion of the cage assembly and the second end of the nut element. a cap retainer coupled to the cage assembly and including a retainer body and a retainer sealing member, the retainer body defining a retainer passage, the retainer sealing member compressed against the mounting plate, a dome cap having a closed end, a cap base, and a cap sealing member, the cap base positioned within the cap retainer such that the cap sealing member sealingly engages a portion of the cap retainer surrounding the dome cap, a nut element having a first end, a second end, and a nut body, the nut body defining a passage for receiving a fastener extending through the metallic expandable portion of the cage assembly and the second end of the nut element.