using scrap of romex sheath as a spacer

I have used the romex scrap, washers, toothpicks, matchsticks or whatever ever did the job. Next time I do one I will do whatever fits.

Colbyt

I would refrain from using anything that can burn.

Caddy makes something that will support a wiring device and compensate for large openings:

Strip a piece of copper wire. Wrap it tightly around a Phillips screwdriver. Pull it off. Cut the appropriate number of coils to space the switch/recep out the proper distance. Materials and tools that you always have when doing plugging and switching. Economical, solid, fireproof, professional.

(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

Doesn't code require a non-combustible box extender when the box is too deep in the wall? So that in theory any sparking from the device won't get lodged in combustible material in the crevice behind the wall surface?

aem sends...

Good point. The situation I was referring to was where the box was less than 1/2 inch behind the face of the wall so there really wasn't a gap with an opening into the wall cavity, but the face of the sheetrock was not square enough against the edge of the box to cleanly hold the metal ears on the outlet.

Thanks for all the great input on this topic!