Rewiring a house is always recommended to be carried out by a qualified electrician. As an electrician or tradesperson, you know rewiring a home is a big project that requires careful planning. But with house electrical wiring regulations, tools and supplies changing frequently, there may be some aspects of the job you haven’t considered. Particularly if it’s a job you don’t do regularly. 

This professional’s guide will give you a clear understanding of what to consider when rewiring a house and the best practice to follow. Discover the signs that indicate a house needs rewiring and what a rewire involves. Learn what Electrical Installation Condition Reports and current wiring regulations are. And we’ll run through a list of the top rewiring supplies and tools. 

If a home hasn’t been rewired for 25-30 years or more, it may need wiring work to bring it up to current standards. But there are other typical signs to look out for that indicate when to rewire a house, such as: 

• The consumer unit trips out regularly, and fuses or bulbs blow 
• There’s a crackling or buzzing noise from electrical sockets 
• The electrical wiring is covered in black rubber, fabric or lead 
• There are signs of burning, such as discolouration around plugs and sockets or a burning smell 
• Lights are constantly flickering, and bulbs need to be changed often  
• There are switches made of cast iron 
• There’s no labelling on the consumer unit 
• The consumer unit has a wooden back 
• Sockets are broken or cracked 
• Sockets have rounded plug entries instead of 3-pin entries 
• There are less than two plug sockets in each room 
• Plugs get very hot 

Please note, it is always recommended that this work is completed by a qualified electrician. 

Rewiring a house typically involves removing old wiring and installing new electrical wiring and all related components as follows:   

• Electrical cables are replaced, and a new consumer unit is installed 
• New cabling is fitted into the walls and beneath the floors 
• Back boxes on all switches and sockets are replaced with new back boxes 
• Power and lighting circuits are rewired 
• Telephone and tv aerial sockets are rewired 
• Switches, sockets and light fixtures are added or moved if required 
• Cabling for new technology, such as speakers, CCTV cameras, automated lighting etc., is added if required 

All of this wiring work can be broken down into two stages, known as ‘fixes’: 

The first fix stage is where you’ll do all the work needed on hidden cabling that must be carried out before plastering. The work typically includes cutting chases and installing cabling into the walls. Then fitting new back boxes for switches and sockets. Rewiring power, heating and lighting circuits. Rewiring phone and TV aerial sockets. Plus, adding cabling for new technology such as burglar alarms, CCTV cameras, smoke detectors, doorbells, outdoor lighting etc.  

When cutting chases into walls, there are some key things to remember to ensure you comply with electrical regulations and don’t compromise the stability of the wall: 

• A vertical chase must not be cut any deeper than one-third of the total wall thickness 
• In a cavity wall, a vertical chase must be no deeper than one-third of the thickness of the skin it’s being placed in 
• No chases, whether horizontal or vertical, should be made back-to-back 
• A horizontal chase must not be cut any deeper than one-sixth of the total wall thickness  
• In a cavity wall, a horizontal chase must be no deeper than one-sixth of the thickness of the skin it’s being placed in 
• Chases must go from A to B in a straight line, vertically or horizontally. There must be no diagonal chases 

The second fix stage is carried out once all re-plastering is completed and the walls are made good. The work typically includes wiring in the faceplates on switches and sockets. Wiring in light fittings. Connecting items such as cookers, extractor fans, electric showers, heating controls etc. Then everything is connected to the consumer unit and tested to ensure it’s all live. 

An Electrical Installation Condition Report is a report that’s written following an inspection of the electrics within a property. Its aim is to find and report any damage or wear and tear that may cause electric shocks, high temperatures or affect its safety in any other way. It also identifies any wiring work that doesn’t meet Institution of Engineering and Technology (IET) electrical wiring regulations and serves as an important record of a home’s electrical wiring condition that’s used in future inspections. 

There are two types of report: 

1. Visual condition report : This type of report is only suitable for properties that have already been fully tested recently. It doesn’t involve any testing, just a visual inspection to confirm the electrics are safe to use until the next inspection. It includes checks such as ensuring electrical sockets aren’t overloaded and appliances have Residual Current Device (RCD) protection.
2. Periodic inspection report: This type of report covers a full inspection and testing of the electrics in a property, including circuitry hidden behind walls. It’s recommended this inspection is carried out every 10 years for private homes and every five years for landlords. 

When homeowners or landlords receive their report, they must have any highlighted faulty or outdated wiring work replaced or fixed. This ensures the house is abiding by the latest UK electrical wiring regulations and the wiring installation is safe. 

The UK’s current wiring regulations (18th edition) are the national standard for all domestic electrical wiring work. They set the rules for the installation of fixed cabling within a property to ensure safety. 

The regulations state the work must be compliant with Approved Document Part P of the Building Regulations, following the rules of BS7671 - often referred to as the IET wiring regulations. They cover the design, installation, inspection, testing and certification of electrical wiring. All wiring work must be completed to this standard.  

1. Planning position of lights, switches and sockets

Careful planning is the key to a successful rewiring job. Before you start, map out where everything will go. Work on a room-by-room basis, deciding where every light, switch, socket and any other electrical point, such as smoke detectors, speakers, security lights, cameras etc., will go. Doing this work up front will save you from making costly and time-consuming additions later in the project.

2. Timings

A rewiring job is carried out in two stages. The first fix stage is completed when floorboards are pulled up, and the walls have no plasterboard or when you've chased out channels from the walls for cabling. This is the stage where all wiring normally hidden behind walls is exposed. Then, the old wiring and electrical components are removed, and new cabling is installed. 

You will need to return after the plasterboard has been replaced and the walls have been made good to complete the second fix stage. This is when you install all the external electrical components, such as switches, sockets and light fittings. 

3. Future-proofing

Our use of technology in the home has increased over the years. And with the growing popularity of smart home technology, that rise is likely to continue. So, when scoping out a rewiring project, consider how the homeowner’s requirements may change over the next 10 years. For example, how many sockets does the home currently have and how many more may be needed to meet future demand? 

4. Smart home wiring

If a home you're rewiring doesn't already have some smart home technology installed, this is a good time for the homeowners to consider it. Setting up wiring for smart home products such as CCTV cameras, doorbells, and heating now will save time, money and disruption later on. And, as smart home products rely on the internet to work, also consider the internet cabling. Most homes rely on a single wired ethernet connection and Wi-Fi. But, by installing extra ethernet connections, the homeowners will have faster internet access now and in the future if their demand rises. 

5. Official certification

After you have completed a rewiring project, you must give the homeowners an official certificate that confirms the work you have carried out meets part P of the Building Regulations. To do this, you must be registered with one of the Government approved Part P schemes.