Systems and methods for electrically connecting conductors of a downhole electric system using connector bodies that includes an outer housing, one or more inner conductors and an inorganic insulating material such as a glass-ceramic material which forms a fluid-tight seal between the outer housing and the inner conductor. The insulating material may be bonded to the outer housing and to the inner conductor. The insulating material may alternatively have an interference fit with the outer housing and the inner conductor. The connector bodies may have standardized connector interfaces to facilitate connection to complementary standardized connector interfaces on cable-end connectors, etc. Connector bodies may be formed as motor heads, mandrels for cable splices, penetrators, etc.