We just had a new marble tile backsplash installed, and are now trying to put the outlet faceplates back on. However, because the tile is blocking the screw hole, we can't screw the outlet covers back on (the faceplates have screws on the top and bottom, not the middle, because they are ground, etc...) Any suggestions aside from trying to drill into our new marble backsplash? (The snap one ones don't work either, as the mounting plate requires screws on the top and bottom)
DO NOT try to chip away the marble no matter how tempting it may be.....most marble is soft enough that you can use a round file to to simply file down the offending edge. You can also use a metal cutting jigsaw blade, held firmly in vise grips, to carefully saw off some marble. Take your time and clear your cutting edge frequently and you can make your cut easily.
I use an awl or small screwdriver, along with a small hammer, to carefully chip away enough tile to allow the screws to work.
It really seems like your tile installer did not cut the receptacle holes large/precisely enough. If possible, make the installer do it so you will not be responsible for any inadvertent cracks or large chips that will be visible.