A method for coupling ends of two insulated conductors includes coupling an end portion of a core of a first insulated conductor to an end portion of a core of a second insulated conductor. At least a part of the end portions of the cores are at least partially exposed. Electrically insulating material is placed over the exposed portions of the cores. An inner sleeve is placed over end portions of the two insulated conductors to be coupled. An outer sleeve is placed over the inner sleeve. There is an open volume between the inner sleeve and the outer sleeve. The inner sleeve and the outer sleeve are coupled to jackets of the insulated conductors. A pressurized fluid is provided into the open volume between the inner sleeve and the outer sleeve to compress the inner sleeve into the electrically insulating material and compact the electrically insulating material.