Abstract: The invention is directed to improvements in electrical cable connectors for safe use with electric motor driven mine equipment in coal mines in which gassy conditions normally create great danger of explosion caused by incendive arcing or sparking. In accordance with the invention the receptacle and plug components of the connector, after being screwed together are locked in operative position by the provision of a padlock the stem of which passed through a hole in a locking ear of a mounting flange on the receptacle component, is engaged as one of a series of undulations in the surface of a compression lock ring on the plug component facing the locking ear.