In NSW, all new buildings are expected to have safety switches mounted, and switches must be added if extensions or modifications are done to an existing building. Rental properties in QLD and VIC must have Safety Switches mounted, and in NSW it is strongly recommended to do so. In some States and Territories, they are a prerequisite before selling or leasing a house. Regardless of the state, when any electrical work is performed on a premise and load on a circuit is altered, a safety switch must be installed. Always seek a professional opinion from your electrician prior to repairs or extensions.