The earth wires have been omitted for clarity and would want to get connected in the least switches and ceiling roses. The wires would also be included via the protecting outer sheath (cable). They are only schematic diagrams to clarify about different kinds of preparations that you may locate when https://smartpowerpointsandswitch55307.sharebyblog.com/34594026/little-known-facts-about-smart-switches-for-home