Turn off the power to any outlets and switches in the wall where the backsplash is being installed at your home's main electrical box.
Go into the room where you are working and remove the plate cover from the outlets. Test the outlets with a voltage tester to ensure that the circuit is off.
Unscrew the mounting screws that hold the outlets to the wall and pull the outlet away from the wall. Loosen the terminal screws on the sides of the outlets and unhook the wires. Place the outlets in a safe location.
Twist the ends of the wires together with plastic connector caps.
Mix a batch of grout, following the instructions on the packaging.
Begin applying the grout to the wall with a grout float. Start at the bottom of the wall and work toward the top of the wall, running the grout float diagonally over the tiles. Remove the tile spacers with needle-nose pliers as you come across them.
Apply grout to the tiles around the outlet in a diagonal direction, but apply the grout going out away from the hole for the electrical outlets. Allow the grout to dry for the time specified on the packaging.
Wipe down the tiles with a damp sponge. Rinse the sponge frequently. When wiping down the tiles around the outlet holes, wipe the sponge away from the edges of the holes to avoid letting water get inside the wall.
Wipe the hazy film off of the tiles with paper towels about 45 minutes after you wipe it down with the sponge.
Reattach the outlets, reversing the steps you took to remove them from the walls.