To comply with government guidelines, it is now a legal requirement to have an electrical safety certificate completed by a licensed electrician. Electrical work must be tested and not violate any regulations before being considered complete.  Under the Electricity Regulations 1947 (the Regulations), all residential premises to be sold, rented or hired must have at least two Residual Current Devices (RCDs) protecting the final sub-circuits to socket outlets and lighting. There must be no more than three final sub-circuits per RCD. The lighting circuits (if there are two or more) must be divided between the RCDs. Aside from having two functional RCDs installed in the building, each property room should be equipped with a hardwired smoke alarm no older than ten years old.