Cables do not need buried at all. They can run on the surface of the walls. There are two main methods. In stud walls, they go down the centre of the wall between the two skins. If the wall is over 100mm thick than the cable could be over 50mm from the sides which would allow you not to use RCD protection. On solid walls then the chase is only just enough to plaster over. So the plaster does not damage the cable it is normally on new builds covered with capping and on rewires with oval conduit. The latter allows a smaller chase to be made. There are two types of cable the twin and earth has been used for years and is by far the most common but there is also flexishield which does not need RCD protections. But with all sockets from 1st July needing RCD protection and also everything in a bathroom there is very little which would not need RCD protection. So I think total RCD protection will be the norm. As to a garage well which type if it is just to store a car in then no difference to a house but if for the repair of cars then better cable protection would be required either conduit or steel wire armoured would be the norm.
Is there any new regulations that i need to e aware of when renewing wiring in a domestic property as i have heard rumours that plugs must be a certain distance away from water outlets now and not just out of reach etc ?????
There are two main sets of regulations. The IET and British Standards issue electrical regulations BS 7671 at the moment either 2001 or 2008 may be used on 1st July BS7671:2008 also known as 17th Edition comes into force. A sink does not come under any special rules and there is nothing to stop you putting a socket very close but it would be foolhardy and since normal lead sets are 1.2 meters that is normally considered the closest you would put it. With the new regulations RCD's are required for most of the house. The other regulation is building control part p and part m are main ones. Part P makes following BS7671 law. And for certain electrical work requires permission or registration to be made. Part M says where sockets may be mounted 400 to 1000 for sockets outlets from floor and 350mm from room corners. Light switches up to 1200mm from floor and if general public are to use them in line with door handles. Thermostats 1200 to 1400mm from floor but I am sure my mum would complain most bitterly if that was done in her house as she would not be able to see dial from her wheel chair. It does mention exceptions and I think it only covers parts of the house visitors may use. Except for houses like my mothers with chair lift up the stairs can't really see why upstairs sockets should matter. The building control regs have links from projects.
Under the new 17th edition the bathroom and shower in bed room regs have been combined and a socket 3 meters from bath or shower is now allowed in both dedicated bathrooms and bedrooms alike. There are about 400 pages in the regulations and exams are set to prove you can read them so can't really give it all here.