An injection molding system with an electric heater has a reusable high temperature electrical connection assembly that provides a very secure small diameter high current inline coupling. The system is comprised of a mold, a heater, connecting wire to a power source and a connector assembly. The heaters and the mold are conventional and well known in the art. The connector assembly, in a preferred embodiment, has a male portion and a female portion. Each is permanently connectable to two wire ends to be removably connected. The male connector portion has a metallic tubular portion with a first end open for insertion and attachment by crimping or brazing of one wire end, and a second end having exterior threads for joining to the female portion. The second end also has a conductive pin integral with the metallic tubing and extending axially outward therefrom. The female portion has another metallic tubular portion with one end open for insertion and attachment by crimping or brazing of the other wire end to be connected, and an opposite end with an opening sized to receive the conductive pin and a flange. A nonconductive nut with internal threads is rotatably positioned on the second metallic tubular portion, adjacent the flange, for engagement with the exterior threads. High temperature resistant insulative tubing is disposed on the metallic tubular portions except for the flange and exterior threads such that the insulative nut is rotatable to secure the male and female and no conductive parts are exposed. The connection facilitates replacement of failed heaters by simply decoupling the connection, removing the heater/connector portion and replacing same with a working heater/connector portion assembly.