I had 5 outlets moved to under my cabinets. The Electrician put a junction box over the old outlets. I now need to install backsplash. Can the tile guy cover the box with the backsplash?
In most countries/states it is not permissible to have a normal wiring join in an inaccessible location.
If you check local code, there may be specialised splices that can be used in inaccessible locations but usually you would have to replace the wiring with continuous wires.