Insulation Piercing Connector 4/0 - 3 AWG Insulation piercing connectors are made for use with copper-copper, copper to aluminum and aluminum to aluminum applications. They are safe to use and are completely insulated, no need to strip wire. They can be installed on energized conductors with no contact at any point. No spacer required between connections. Exclusive "turbo spacer" keeps tap side open while main conductor is being tightened. Watertight and corrosion-free.