Wall chaser from angle grinder - video

[jdurand]

When you have masonry walls and want to run a wire or water pipe, you need to cut a trench in the wall, lay in the item, then hard plaster over it.

When a wall is new you only sink in the electrical boxes and plaster over the wires. Water pipe are still chased in since they're too big to simply cover over.

The below picture is from our new home. You'll see the junction box is sunk in but the wires are on the surface of the brick. This all gets hidden behind hard plaster/stucco. If I later need to run another wire I'll need to make a trench.