A modular truss assembly configured to be placed in small or narrow spaces such as within the floor, sidewall, or crown of a vehicle for mechanically and electrically mounting system components of a modular equipment center (MEC). A plurality of MECs is spatially distributed throughout the vehicle to service equipment loads. The modular truss assembly provides different voltage levels for powering the system components of the MEC and for powering the equipment loads. In one or more configurations, all or part of the modular truss assembly can be removed from the vehicle for repair or replacement.