An electrical isolator includes a flexible non-electrically conductive membrane and an inelastic flexible dielectric member journalled in the membrane and extending from the first end of the membrane to the second end of the membrane. First and second couplings are mounted to the ends of the dielectric member. The ends of the membrane are mated in sealed engagement with the couplings so as to fluidically seal the ends of the membrane and the dielectric member within the membrane. The membrane is filled with a dielectric fluid so as to displace any air in the membrane and the dielectric member. The couplings are adapted to couple to objects at opposite ends of the electrical isolator.