Surface mounting - What is the difference between a flush mounting and surface mounting?

With a flush-mounted switch or socket, the mechanism is installed in a flush-mounting box inside the wall. With a surface-mounted switch or socket, the mechanism is installed on the wall using a surface-mounting box or surface-mounting kit.

Surface mounting is particularly suitable when you do not want to or cannot install flush-mounting boxes and want to minimise the need to cut channels into the wall. This is useful, for example, in renovation projects, technical rooms and on concrete or brick walls.