Advanced Drilling: How to Set a Fixture Inside a Large Format Tile.

Use a high quality diamond cord bit.

Use plenty of water for lubrication.

Mark the area you will be drilling through.

Use a wooden pattern to guide the coring bit.

Drill on a stable surface.

Drill at a slow speed with a water source lubricating the drill and glass.

Superimpose a second hole to create an opening large enough to cover the receptacle.

Remove all glass pieces. Insure the cutout is large enough.

Install tile and receptacle.

Replace cover plate.