a modular enclosure system for electronic equipment is disclosed as is a process for assembling such a system . the basic element of the system is a frame unit which forms a chamber for the electronic equipment . each frame unit has front , rear and side openings . around each opening is a flange and a push - on bulb seal . a generally rectangular cross - sectioned seal is adhered to comer posts of the frame unit . doors are mounted to the frame unit to seal the front and rear openings by compressing respective bulb seals . side panels are mounted to the frame unit to cover side openings of a single or multi - frame unit system and the side panels compress both types of seals mentioned above . bridge panels connect adjoining , aligned frame units and compress the rectangular seals and also result in bulb seals mounted around adjoining side openings of adjoining frame units to compress each other . battery housings , covers and skids are also connected to aligned frame units as is a single cap panel . the system is simple , economical , easy to handle , east to install and easy to expand .