Welded or Tabbed Switch Box:
Although these boxes look similar to a gangable box, they are very different. These non-gangable switch boxes are made from flat steel plates and may have interlocking tabs and/or spot welds holding them together. They cannot be taken apart and are not gangable. They are available in single gang, 2 gang, 3 gang or 4 gang box sizes.
Two holes are usually found at the back of the box for nailing the switch box to the stud. Sometimes these new work boxes will come with a tab or bracket attached to one side for fastening the box to the wood stud when using box in single or multiple gang box configurations.
