Abstract: A penetrator connector assembly is suitable for connecting two parts of an electrical conductor across a pressure barrier in an oil or gas well. The assembly includes a body with a bore for an electrical conductor, a sealing boot that seals an annular space between the conductor and the bore, and a port that transmits a pressure differential between the exterior of the body and the annular space, so that the pressure differential acts on one side of the sealing boot to apply a compressive force and enhance the seal. The assembly also has a spring that can be resiliently energised to apply a compressive force to the sealing boot independently of fluid pressure differentials.