Evolution of insulation piercing connector technology

In order to eliminate the inconveniences of rubber and PVC insulated cables, EdF, in association with Aluminium Pechiney connector manufacturers, investigated three main issues: (1) find a more resistant insulation layer; (2) improve contact reliability; and (3) connect customers under voltage and in safe conditions. XLPE (cross linked polyethylene) was chosen in 1977 and is now the most well known insulation material used in LV insulated overhead lines due to its high environmental and mechanical resistance. In order to avoid insulation stripping, EdF spent two years investigating insulation piercing technology. Every 2 or 3 months, EdF went to the site with the connector supplier and carried out resistance measurements. Finally, the piercing technology was born in the 1970s at the same time as in other European countries (Germany). In addition to the above, insulation piercing technology brought an additional safety factor to live line work with no need for wire stripping and an easy and quick connection procedure. The development of XLPE insulation piercing connector technology during the 1970s-1990s is discussed. Test requirements are also outlined.