Electrofusion Welding is a method of joining HDPE and other plastic pipes using special fittings that have built-in electric heating elements which are used to weld the joint together. The pipes to be joined are cleaned, inserted into the electrofusion fitting and a voltage is applied for a fixed time depending on the fitting in use. The built in heater coils then melt the inside of the fitting and the outside of the pipe wall, which weld together producing a very strong homogeneous joint. The assembly is then left to cool for a specified time. Welding heat and time depends on the type and size of the fitting.