Environmentally-isolated electrical junction box and method of installing and servicing the same

A double containment electrical junction box is interfaced with electrical equipment in an equipment enclosure containing harmful contaminants, such as noxious gases and odors generated in a wet well containing a submersible electrical pump that pumps waste water from the well. A lower container contains electrical wiring connected to the pump, and is in gaseous communication with the well for enabling the contaminants from the well to enter the lower container. An openable upper container contains electrical junctions for the electrical wiring from the lower container. Cable and integrity seals between the containers prevents the contaminants in the lower container from reaching the upper container, to prevent migration of the contaminants away from the lower container.