The image below shows that the outlet box is slightly misaligned with the hole in my backsplash. I am debating how I should go about attaching the outlet to the backsplash. I could have the hole enlarged but it will be cutting it short and it might be too big. Another option I am considering, but I am not sure how to act on, is to put a thin piece of metal on the other side of the backsplash and have the screw act as clamps.
Am I missing something obvious, or is there an easier method?
There are multiple problems here. But basically the solution is either:
Cut a bigger hole. Add a box extender to get to the front of the backsplash. Install the receptacle.
Cut a bigger hole. Mount the box so that it is actually in the backsplash hole, with the front at the front of the backsplash.
Which solution you choose will depend on how easy it is to access the box. If you can remove and replace the backsplash without a lot of work, I would take it off, cut the bigger hole and then remount the box so that it fits in the backsplash instead of using an extender.
You can get larger-than-normal Decora-style faceplates, so that if the hole is cut a little big and/or ragged, nobody will ever see that.
I guess you had a "professional" do it this way, and you're thinking since a professional did it, it must be right. Afraid not.
As others have said, Code requires outlets be mounted INSIDE listed junction boxes that is rated to safely contain the kinds of electrical problems that happen inside junction boxes. The box must come flush to the wall... with one exception, if the closely surrounding material is known to be fireproof (e.g. drywall, concrete or stone), the box can be up to 1/4" (6mm) short of the wall.
Not 2 inches lol.
As manassehkatz says, you will need to enlarge the hole. To keep the enlarging to an absolute minimum, I would use a 2-pronged attack:
Use the smallest box available, a metal "Handy-Box". These are available as extender boxes that can stack off the box you have... although if you want extenders of arbitrary thickness, that may be tricky to obtain. Don't waste time at big-box stores, talk to a proper electrical supply house.
Move the GFCI so it isn't here. Because GFCIs can't fit inside Handy-Boxes. (it is extremely difficult at best!) This requires you grasp a huge concept about GFCI protection: GFCI is not a receptacle! It is a zone of protection. A GFCI in one location can provide GFCI protection to outlets elsewhere. So wherever the power to this outlet comes from, put the GFCI there. If it's a breaker, that's fine, they make GFCI breakers.
As a first step I would put a screw in that bottom hole of the electrical box and measure to the edge of the hole. If that measurement is greater than 5/8" then a standard electrical plate won't work. If it's greater than 7/8" then an oversize plate won't work either. Even if it's greater than 7/8" you may still find a "custom" plate at a design shop that will work. What is on the other side of the wall, can you access the box from the other side to adjust it? What is the backslash made of, some solid surfaces can be patched? In any event I would follow the advice from @manassehkatz-moving-2-codidact as far as getting the box code compliant.
