Harmonised test for the measurement of residual methane in insulating materials

Methane generated during the peroxide cross-linking of the power cable insulation system is a major cause of concern for the cable industry, mainly due to the explosive nature of mixtures of methane with air which can be experienced during cable jointing and termination work. It is therefore common practice to degas cables, especially high and extra high voltage cables which have thick insulation layers, to reduce the amount of methane and other decomposition products from the peroxide cross linking decomposition reaction. In this context, it is of utmost importance to have a reliable method for the measurement of the methane content in the cable insulation system. Such a method would make it possible to demonstrate the compliance of the cable with respect to safe methane concentration levels.