Dimming - What is the difference between a 2-wire dimmer and a 3-wire dimmer?

A 2-wire dimmer is usually installed during renovation projects in homes that were built before 1991. These types of house are usually fitted with flush-mounting boxes with only 2 electric wires: the phase conductor from the grid and the switching wire to the lamp, luminaire or light fitting.

A 3-wire dimmer is mainly installed in new-build projects where houses are constructed later than 1991. These new-build homes have 3 electric wires available at the flush-mounting boxes; the phase conductor from the grid, the neutral conductor to the grid and the switching wire towards the lamp, luminaire or the light fitting.