Electrical Boxes: Old Work or Renovation Metal Switch Boxes

By Bob Formisano, About.com Guide

Similar to new work switch boxes, old work boxes are basically the same metal box construction except that they have some mechanical way of fastening the box to the wall material instead of the wood stud as in new construction. This fastening is usually accomplished by some type of ear or flange mechanism that is drawn against the back side of the wall material (drywall or plaster) as a screw on each side of the electrical box is tightened.