A modular enclosure that can be used as a stand-alone unit or can be ganged together in a multiple unit configuration. The enclosure system consisting of a base frame and front door with open sides which can accommodate various side covers or attachments all using the same common mounting. The common mounting used to attach the various covers or attachments provides a unique design for attaching and sealing the side covers or attachments while providing a water-tight and dust tight seal between the interior of the enclosure and the exterior of the enclosure. A variety of attachments are available which give the modular enclosure flexibility to be configured in a wide variety of ways.