Abstract: An improved electrical connector configured to couple high-voltage signals with minimal risk of corona discharge includes a plug assembly having a cylindrical nose and a receptacle assembly having a cylindrical cavity, with a cup-shaped resilient seal carried either in the cavity or on the nose. The seal is sized such that the nose can be manually inserted fully into the cavity while encountering only minimal mechanical resistance. Thereafter the seal's cylindrical side wall is longitudinally compressed, to increase its radial thickness and thereby substantially fill the annular space between the nose the cavity side wall. The connector thus can be coupled and uncoupled with only minimal insertion forces and with substantially reduced risk of mechanical damage.