House Wiring

Ring Circuits

In UK homes, the standard wall sockets are usually connected to a ring circuit or ring main. The ring main in a domestic home supplies sockets and fixed appliances.

The ring circuit itself is created as the cable from the consumer unit leads to the first socket, and then onto the next, and continues until the cable again reaches the consumer unit. This means that the ring main consists of every socket having two cable routes leading back to the supply.

In older properties the cables for the ring main are sometimes fed through the wall cavity, whereby the cables enter through the back of the wall mounted socket. This is no longer a fixture in new homes, as cables within the cavity can become wet and cause moisture to enter the socket.

If old houses are rewired, new cables should be run through ducting in the inner wall or under floorboards.

Each ring main has a 32 amp fuse or trip installed in the consumer unit to protect it. In modern installations, a Residual Current Device (RCD) trips the entire system if it detects a fault.

Electrical appliances like cookers and showers use a lot of power, and as such should not be connected to a ring main unless they use less than the 30 amp current rating of the ring circuit. If they are connected to the ring main, it will cause trips in the consumer unit and will reduce the number of other appliances that can be used at the same time. These should be connected to the consumer unit using a specified fuse or trip and cable run.

There should ideally be two ring circuits in all properties; one for each floor in houses. A separate ring for kitchen can also be beneficial, due to the amount of electrical appliances present. This also means that the freezer will not defrost if there is an issue elsewhere in the house.

Sockets

Conventional electric sockets must not be installed in bathrooms, and similarly light switches cannot be near the wet area of bathrooms. They must be positioned some distance away, outside the room or set in the ceiling and switched on by a pull cord.

Shaver sockets are designed for safe use in the wet area of bathrooms, and are compliant with BS 4573 safety regulations.

Telephones

Standard UK telephone lines have two copper wires that are twisted loosely together, and connect from the local telephone exchange to the house’s master socket. There are generally two lines coming into the house so that a second line can be installed.

The copper pair of wires connects to the master socket and is converted into three wires, two of which lead to telephones and extension sockets round the home. The third wire carries the ringing signal in the UK network.