Barrier joint is a very compact special type of screened joint and so constructed that each joint is itself a barrier to the flow of compound from the joint or the migration of compound from a high to a low level. In this type of joint, no liquid oil compound is used. The insulation consists of a hand applied paper tapes impregnated and coated with styrene which on being heated slowly polymerizes into a hard solid mass and forms a complete barrier. “Barrier joint” is also known as Styrene joint. This method is specially useful for high voltage 3-core cable as the joint is mechanically rigid and displacement of the cores can not occur.