House rewires

Cable does not wear out on a timetable, so age alone is not the reason to rewire. The reasons are what the cable is made of, what has been done to it since, and how it tests.

• Rubber-insulated cable, from before PVC became standard. The rubber goes brittle and cracks when it is disturbed, which is exactly what any new work does to it.
• Lead-sheathed cable, which is older still.
• Early PVC that has spent decades next to heat, above light fittings or buried in loft insulation.
• No RCD protection anywhere, often with rewirable fuses still in the board.
• Decades of alterations: spurs taken off spurs, junction boxes under the floor, sockets fed from the lighting, and three kinds of cable in one circuit.

Round-pin sockets, black rubber or fabric-covered flex, scorch marks and sockets that run warm are all signs worth an inspection. Much of Sandhurst and Bracknell was built between the 1950s and the 1980s, and some of those houses still have a good part of their original wiring, with everything since added on top.

Before anyone lifts a floorboard, it is worth knowing what you have. An Electrical Installation Condition Report (EICR) inspects and tests the existing wiring and records what it finds, circuit by circuit. Low insulation resistance, rubber cable, missing earths and damaged cable all show up in it.

Sometimes the report shows the wiring is sound, and the right answer is a new consumer unit and a few repairs. Sometimes it shows that patching it up would cost more than starting again. Either way, you decide with the results in front of you.

Older lighting circuits were often wired with no earth conductor at all. That rules out metal light fittings, and on its own is a good reason to look at rewiring the lighting.

A full rewire replaces every circuit: the cable, the back boxes and the accessories, and normally the consumer unit, so the whole installation is new and certified together.

A partial rewire replaces part of it: one floor, an extension, the kitchen, or the circuits that tested badly. It makes sense when the rest of the installation is in good condition, because the new work connects to it and relies on its earthing and protection.

If a partial rewire would leave new cable joined to old, or an old board in charge of new circuits, we say so and explain the choice. The written quote lists which circuits are being replaced, what is being kept and why.

Most rewires are done with the family still at home. The work moves through the house in an order agreed with you, so you know which rooms need clearing and when.

• Furniture goes to the middle of the room and is covered, or out of the room if you can manage it.
• Carpets and floor coverings need lifting wherever floorboards come up.
• Chasing walls makes dust. Rooms are sheeted, doors kept closed, and we clear up as we go.
• The power is off while circuits are being changed over. The programme that comes with the quote shows when, so you can plan around it.

An empty house is easier to work in, so if you are between owners or renovating anyway, that is a good time to do it.

A rewire happens in two stages, with the making good in between.

1. First fix. Floorboards come up, walls are chased and new cable is run to every point. Cable goes through holes drilled in the middle of the joists, not notches cut in the top where a floorboard nail can reach it. A new back box goes in for every socket and switch.
2. Second fix. Sockets, switches and light fittings go on, the circuits are connected to the consumer unit, and everything is tested.

Cable buried in a wall runs straight up, down or across from the switch or socket it serves. These are the safe zones, and they mean anyone drilling into the wall later can tell where the cable is likely to be. Cable in the zones also has 30 mA RCD protection.

Chases are filled, back boxes set flush, and floorboards screwed back down so they can be lifted again later without damaging the cable underneath.

Filled chases still need finishing and painting. The quote says exactly what making good includes and what is left for a plasterer or decorator, so nobody is surprised.

If a new kitchen, bathroom or extension is on the way, tell us early. Rewiring before the new surfaces go in saves cutting into them afterwards.

Each new circuit is tested for continuity, insulation resistance, polarity and earth fault loop impedance, and every RCD or RCBO is tested to confirm it disconnects as it should. The earthing and the bonding to the gas and water pipes are checked, and put right as part of the job where needed.

The results go on an Electrical Installation Certificate (EIC), which records what was installed and every reading. Work is to BS 7671, the IET Wiring Regulations.

A rewire is notifiable under Part P of the Building Regulations. A registered installer self-certifies the work and notifies building control for you, and you receive a Building Regulations compliance certificate. Locally, building control is Bracknell Forest for Sandhurst and Bracknell, Surrey Heath for Camberley, and the Royal Borough of Windsor and Maidenhead for Ascot.

• New cable to every point, in the safe zones or protected, and through the joists rather than over them.
• A consumer unit with 30 mA RCD protection and a circuit chart in the door.
• Sockets and switches where you want them, agreed before first fix.
• The Electrical Installation Certificate, with the test results for every circuit.
• The Building Regulations compliance certificate. Keep both with the house paperwork; a buyer’s solicitor will ask for them.