These electrofusion entry seals weld directly to the walls of polyethylene chambers or sumps. They have been specifically designed to reduce the number of fittings necessary to provide water tight seals between the underground tank sump/chamber and the UPP primary or secondary contained pipe and electrical conduit or duct. The nature of the seal means that after installation it becomes one with the sump, with zero leak paths, creating a 100% leak tight system. The seals are polyethylene based allowing electrofusion of UPP pipework systems directly to the penetration, negating the need for mechanical boots and creating a homogeneous structure of the sump, boot and pipe.