Abstract: A control apparatus or system for purged and pressurized electrical equipment provides rapid, controlled exchange of pressurizing or purging gas to an electrical enclosure. The control system or apparatus for NFPA Type Y and Type Z electrical equipment enclosures has a source of pressurizing gas, a rapid exchange pressure control filter/regulator, rapid exchange pressure gauge, vent control valve and a manual inlet valve providing for rapid exchange of purging gas to the electrical enclosure during start up, an enclosure control valve, enclosure pressure indicator, a venturi providing controlled leakage from the system, and a pressure loss control alarm or switch.