At best, to replace a switch, capacitor, or cord on the site has been a costly, time consuming task. The modular end dome houses the switch, capacitor and 7" pigtail with positive locking device, and can be quickly removed as a unit without removing fastening screws and replaced with a new or rebuilt unit at the fan location. the removed end dome can then be rebuilt conveniently and rapidly with a new switch, capacitor or pigtail on the bench in the maintenance area and used for the next modular replacement.