TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Fuel Cell Installation: The interfacing structure is mounted on the support structure with a bearing arranged between the support structure and interfacing structure in the installed position. The bearing is a spherical bearing permitting rotation of the interfacing structure relative to the support structure. The interfacing structure includes interlocking features between the support structure and interfacing structure limiting rotation between them. The interfacing structure includes a dielectric bushing arranged between the bearing and the cell stack assembly electrically insulating the cell stack assembly relative to the support structure. The interfacing structure includes a tapered pin extending from the cell stack assembly and received by the bushing in the installed position. The connector is captured within an aperture of the plate and movable in a plane relative on it, where the connector includes a lip and a retainer axially locating the fluid connector within the aperture and permitting movement of the connector in the plane. The fitting is a fluid fitting, and the fuel cell comprises a seal arranged between the fitting and the connector, where the fluid fitting is arranged on a rear end of the cell stack assembly and other fluid fittings are arranged on a front end opposite the rear end, the rear end inaccessible during the installation procedure. The fluid fitting is a coolant fitting. The other fittings include electrical, fuel and reactant fittings. The fitting is an electrical fitting. The cell stack assembly is slidable along an installation direction relative to the support structure during the installation procedure, the installation direction generally perpendicular to a plane provided by the interfacing structure. Preferred Method: In the method of installing a cell stack assembly into a support structure, inserting step includes sliding the cell stack assembly on the support structure in the installation direction. The cell stack assembly includes a pin, and the support structure includes a plate supported by the support structure in a plane transverse to the installation direction, the engaging step including engaging the plate with the pin, and the repositioning step includes moving the plate in a plane. The plate carries the fluid connector, and the repositioning step includes moving the fluid connector relative to the plate in the plane. Engaging step includes electrically isolating the pin from the support structure. Engaging step includes sealing the fluid fitting relative to the fluid connector.