Low-energy faults, such as partial discharges of the cold plasma type (corona discharges),favour the scission of the weakest C-H bonds (338 kJ/mole) through ionization reactions and the accumulation of hydrogen as the main recombination gas. More and more energy and/or higher temperatures are needed for the scission of the C-C bonds and their recombination into gases with a C-C single bond (607 kJ/mole), C=C double bond (720 kJ/mole) or CºC triple bond (960 kJ/mole), following processes bearing some similarities with those observed in the petroleum oil-cracking industry.