Abstract: An expandable moulded cabinet for housing printed circuit boards, which is modular and uses only two kinds of parts. Instead of printed circuit board retainers and a backplane being fastened to a cabinet frame, which would require careful attention to tolerances, the retainers are held by the cabinet in approximately correct positions, and the backplane is supported by and is fixed directly to the retainers alone, and not the cabinet. Thus the only precision tolerances required are to the locations on the backplane where the printed circuit board retainers are supported. An inexpensive and versatile cabinet results.