A fitting for coupling ends of insulated conductors includes a sleeve to couple an end of a jacket of a first insulated conductor to an end of a jacket of a second insulated conductor. The sleeve is located between end portions of the insulated conductors. At least one of the ends of the sleeve is angled relative to the longitudinal axis of the sleeve. The sleeve has a longitudinal opening that extends along the length of the sleeve substantially the distance between end portions of the jackets of the insulated conductors. The longitudinal opening allows electrically insulating material to be filled into the sleeve.