A system for isolating electrical current in an aircraft structure, the system comprising: a first structure; a second structure; a bearing comprising: an outer race defining an outer race inner surface and an outer race side surface; an inner race disposed partially in the outer race and coupled to the second structure, the inner race defining an inner race outer surface; and a liner disposed between the outer race inner surface and the inner race outer surface; the first structure being coupled to the outer race; a dielectric seal secured to the outer race side surface and sealingly and slidingly engaging the inner race outer surface; a sealed chamber defined by the dielectric seal, the outer race inner surface, the inner race outer surface and an edge of the liner; a conditionally non-conductive gas for conditionally electrically isolating the first structure from the second structure, the conditionally non-conductive gas fluidly occupying the sealed chamber; and characterized in that the sealed chamber defines a minimum gap between the inner race outer surface and the outer race inner surface, the gap has: a predetermined magnitude sufficient to prevent electrical arcing or current leakage between the inner race outer surface and the outer race inner surface at a first voltage, the first voltage being less than a voltage resulting from a lightning strike; and a predetermined magnitude sufficient to conduct an electrical current between the inner race outer surface and the outer race inner surface at a second voltage, the second voltage being at least as great as the voltage resulting from the lightning strike. a first structure; a second structure; a bearing comprising: an outer race defining an outer race inner surface and an outer race side surface; an inner race disposed partially in the outer race and coupled to the second structure, the inner race defining an inner race outer surface; and a liner disposed between the outer race inner surface and the inner race outer surface; an outer race defining an outer race inner surface and an outer race side surface; an inner race disposed partially in the outer race and coupled to the second structure, the inner race defining an inner race outer surface; and a liner disposed between the outer race inner surface and the inner race outer surface; the first structure being coupled to the outer race; a dielectric seal secured to the outer race side surface and sealingly and slidingly engaging the inner race outer surface; a sealed chamber defined by the dielectric seal, the outer race inner surface, the inner race outer surface and an edge of the liner; a conditionally non-conductive gas for conditionally electrically isolating the first structure from the second structure, the conditionally non-conductive gas fluidly occupying the sealed chamber; and characterized in that the sealed chamber defines a minimum gap between the inner race outer surface and the outer race inner surface, the gap has: a predetermined magnitude sufficient to prevent electrical arcing or current leakage between the inner race outer surface and the outer race inner surface at a first voltage, the first voltage being less than a voltage resulting from a lightning strike; and a predetermined magnitude sufficient to conduct an electrical current between the inner race outer surface and the outer race inner surface at a second voltage, the second voltage being at least as great as the voltage resulting from the lightning strike. a predetermined magnitude sufficient to prevent electrical arcing or current leakage between the inner race outer surface and the outer race inner surface at a first voltage, the first voltage being less than a voltage resulting from a lightning strike; and a predetermined magnitude sufficient to conduct an electrical current between the inner race outer surface and the outer race inner surface at a second voltage, the second voltage being at least as great as the voltage resulting from the lightning strike.