An electrical connector which can be used for pipe line heaters includes a base, an insert having a slot therethrough for a conductor, and a crimp barrel for the insert. A cap fits over the barrel and cooperates with the barrel and base so that when the cap is filled with a viscous potting compound, and the cap is slid over the barrel, the potting compound is pressured so that it substantially completely fills the cap and the base, thereby environmentally sealing the resulting assembly.