The main difference between conventional hot melt and electrical fusion is the method of applying heat. In traditional hot melt (butt, saddle and socket) connections, heating tools are used to heat the pipe and fitting surfaces. The fused joint is heated internally or by a conductor at the joint interface or by a conductive polymer. Heat is generated when current is applied to the conductive material in the fitting. Electro-fusion joints are required for PE pipe-to-tube connections made using the electrofusion process.