from 1st July 2008 one of the major changes of the BS7671:2008 17th Edition IEE Wiring Regulations is that all circuits, ie, power, lighting, shower, cooker etc, should be protected by a 30 milliamp RCD (Residual Current Device) for any cables installed at a depth of less than 50mm from a surface of a wall or a partition, where the cables do not incorporate mechanical protection or earth metallic covering etc. This situation will usually be the case for installations in domestic or similar premises unless the installation is intended to be under the supervision of a skilled or an instructed person.
