Does Your Home Improvement Project Require New Wiring?

Whether or not your property requires rewiring is an important consideration when deciding whether or not to embark on a renovation project. If the house you're looking to buy is more than 25 years old, you should look into the condition of the wiring before you buy.  

You can estimate how much work will be required by conducting a survey ahead of time. This also means you'll be able to get an estimate of how much rewiring is likely to cost — which may affect whether renovating a house is feasible for your budget.  

Not to mention that rewiring can be a messy and disruptive job, so budget for repairing the walls and ceilings after the rewiring process is completed.  

Your home's rewiring is also not a place to cut corners. At worst, bad wiring can cause a serious fire hazard as well as injure or electrocute those who live in the house.  

In this guide, we will look at what you need to know about the rewiring process from the standpoint of a renovator.  

A home may require rewiring for a variety of reasons, including:

• If a property has not been rewired in the last 25-30 years, chances are it will require some upgrading to bring it up to current standards. The wiring could be dangerous and incapable of meeting the demands of modern living.
• If you intend to do major remodeling that constitutes a material alteration as defined by the Building Regulations, you will almost certainly need to rewire a portion, if not the entire property, including upgrading the consumer unit (fuse box).
• If you are extending your home or converting an attic or garage, this will be considered new work, and all new wiring must comply with Part P: Electrical Safety. (Opens in a new window) , and all existing wiring will need to be upgraded to ensure that it can safely carry the additional loads, that it is earthed to current standards, and that cross bonding is satisfactory.
• The rest of the existing wiring does not need to be upgraded unless it is required by the Building Regulations' energy efficiency requirements, i.e. e controls for central heating

How to Determine Whether Your Property Has Been Rewired

If a house has recently been rewired, you should be able to tell by inspecting exposed wiring as well as the electricity meter and fuse box (now known as the consumer unit). You can request this when touring a property you are considering purchasing or when inspecting your own home. If there is an old-fashioned fuse box with big white ceramic-style fuses, chances are the property needs to be completely rewired.

When working with two or more sets of circuits, it can be difficult to know if all of them have been disconnected, which is dangerous. A mix of different socket and switch styles is another sign that a rewire is required. This could indicate a partial rewire, especially if surface-mounted wiring is visible running along skirting boards and up walls.

In rare cases of properties that have not been renovated in decades, you may still find old round pin sockets or original dolly switches, both of which are a dead giveaway that a rewire is required.

Another indicator is the color and style of the cabling, which should be visible at light fixtures and around the fuse box. Modern electrical installations are wired with grey or white PVCu insulated cable, and a modern consumer unit will have circuit breakers and residual circuit devices (RCDs).

(MORE: Locate an electrician for your project.) (Opens in a new window) )

What if it wasn't rewired?

A rewire is likely to be required unless the wiring is modern PVCu coated type. If you come across any old rubber insulated cabling, fabric insulated cabling (used until the 1960s), or lead insulated cabling (used until 1955), it should be replaced because the insulation can rot and/or break down, resulting in short circuiting: a fire hazard and potential electrocution.

Even older PVCu cable may require replacement if it is not twin earthed (with a second earth cable running within the outer sleeve), but this may only be apparent if you can remove a switch or socket faceplate and inspect it carefully.

Checking for this while viewing is not recommended unless you are able to turn off the mains first.

If in doubt, assume that a complete rewire is required and budget accordingly. It's possible that by upgrading earthing and cross bonding, the system can be improved for less money.

If you proceed with the project, you can arrange for a qualified electrician to conduct a building survey to determine exactly what work is needed before exchanging contracts.

• A survey with a verbal report will typically cost between £100-150.
• A full electrical survey with a written report will most likely cost between £250 and £350.

How Disruptive Is House Rewiring?

Rewiring a house is a messy, disruptive job. It occurs in two stages: the first, when cables and wiring are installed, and the second, when everything is connected or made 'live,' when the front faces of sockets, switches, and lights are installed. Because those wire runs run everywhere: under floors, through walls, and across ceilings, the initial fix is best done without carpets or furniture, allowing floorboards to be lifted and ceilings to be cut into. Plaster generally needs to be chased into to position new sockets and switches at legally correct heights.

This is why it's critical to plan what's going where in each room before beginning the first fix stage, so you know where you'll need lights, plug points, and any other electrically powered items. Mid-project additions are expensive and time consuming.

One way to prepare is to draw a floor plan of your house with each room marked up with the location of beds, sofas, kitchen units, and so on. You can then think about the necessary lighting and switches. Little things like under-cabinet and bedside lighting are simple to install when planned ahead of time, but costly to install later. Along with task, mood, and feature lighting, keep in mind smoke and heat alarms, garden RCD safety sockets, and external security lights.

Today's society is obsessed with smart home technology. In terms of electronics, this includes mood lighting, surround sound, high-speed Wi-Fi, kitchen gadgets, and bathroom TVs. Electrical circuits must be up to the task — and you must plan ahead of time. Do you want an ethernet cable running through every room to ensure continuous Wi-Fi (or maybe just the living room and bedrooms)? Are you looking for speakers in each room or a security system?

Full rewires are typically done when homes are empty, but for hardened homeowners, it is possible to live in one room while work is being done around you. If you are unable to relocate, dust-cover furniture and expensive items, preferably moving electrical equipment into a separate room, as this is not the responsibility of your electrician. Hire an electrician to install the new consumer unit and provide a temporary supply of sockets in your living space.

How Much Does Rewiring a House Cost?

For a kitchen extension, the cost of rewiring, including the first and second fix with standard sockets and switches but excluding light fittings, should be around £1,000-£1,500. The average cost of rewiring a three-bed semi in the UK is £3,500; the cost will vary depending on where you live. Other factors include the size of the house, its accessibility/emptiness, and the complexity and quality of the finish.

However, if the existing cabling is sound and capable of carrying any additional loads, it may be possible to upgrade it by adding a modern consumer unit, proper earthing arrangements, and cross bonding.

How Long Does House Rewiring Take?

A kitchen rewire could take two days, and a three-bed semi could take two days to first fix, then two days to second fix. A larger property will take significantly longer.

When Does a House Need to Be Rewired?

If rewiring is required, it should be done during the first fix stage (before plastering) along with any central heating and plumbing work. Because new cabling cannot be surface mounted, the installation will entail lifting the floor coverings and floorboards, as well as possibly the skirting boards, as well as routing out channels in the walls and possibly in some ceilings that are inaccessible from above. All of this work will cause significant disruption, so it is best not to try to live around it if at all possible.

In addition to installing new cabling, the first fix stage will include installing new back boxes for all sockets and switches. In addition to rewiring for all power and lighting circuits, this is an excellent time to rewire for modern central heating controls, alarms, smoke detectors, and doorbells, to install outdoor lighting and sockets, and to rewire telephone and television aerial sockets. It is also worthwhile to redesign the wiring plan for sockets and switches to ensure that it meets your requirements as well as the needs of modern home buyers.

Consider specifying two-way or even three-way switching for hallways, landings, and other rooms with multiple main entrances. Consider adding a separate 2 amp circuit with separate switching for table and standard lamps in the main living rooms and principal bedrooms for a high-value property. Consider adding automated lighting, home network cabling, speaker cabling, and other modern technology.

If the mains connection and meter need to be relocated, the local electricity utility company must do so. There will be a fee, and several weeks' notice is required.

After the first stage of repair is completed, the property can be re-plastered, or the walls and ceilings can be filled and repaired, and the flooring replaced. Fitting electrical sockets and switch plates, light fittings, the consumer unit, and wiring any electric fans, cookers, extractor hoods, electric showers, and the immersion heater, if there is a hot water storage cylinder, can then begin.

If you're working on a period building with vernacular materials like oak frame, cob, or solid stonework, make sure your electrician is aware of this and has experience with such structures.

Examining Earth Bonding

Earth bonding, also known as equipotential bonding and cross bonding, is required for the safety of any electrical installation. Even if your renovation does not necessitate rewiring, ensure that the kitchen and bathrooms are earth bonded. Earth bonding ensures that if a fault occurs, the metal plumbing, bath, taps, radiators, or boiler casing will not become live. e Current passing through them will not result in electrocution.

The lack of earth bonding is frequently overlooked because it has no effect on the operation of the electrical circuits in the house. Look underneath the sink or bath for metal clamps around the copper pipes with green and yellow striped earth cable attached to see if your project has been earth bonded. Earth bonding is required for all pipes entering and exiting the boiler and heating system.

If you use plastic pipe instead of copper pipe, you do not need to earth appliances, but you must earth the mains stopcock. If this is not the case, make plans to have this work completed because it is a critical safety requirement.

Wet Area Electrics

Electrical work is restricted in wet areas because of the increased risk of electrocution. Other than shaver sockets, which must be located away from the splash zone from showers, no power sockets are permitted. Pull-cord switches or IR-type switches powered by a battery or a very low voltage signal cable, such as Cat5e, should be used in a bathroom design.

Electrical appliances used in wet or damp environments (except shaver points), such as electric showers, lighting, and ventilation fans, must have moisture and mechanical protection, which is referred to as an IP or Ingress Protection number. The letters IP are followed by two characters in the IP rating. The first specifies the level of resistance to particles or solid objects. The second specifies the level of liquid protection.

The best bathroom lighting may not have the highest IP rating for all areas, as the designs of this lighting become more limited as ingress protection becomes more important.  

The I E E Wiring regulations (BS 7671: 2001 Section 601) include mandatory requirements for areas with a bath or shower. These safety standards are divided into zones, with the requirements for each zone determined by the perceived risk of electric shock. There are four zone classifications: 0, 1, 2, and 3.

Zone 0: The bath or shower. Any fittings used here must be SELV (max 12V) and IPX7 (protected against water immersion).

Zone 1: 2 feet above the bath or shower. 25m A minimum IPX4 rating is required.

Zone 2: The area from 0 to 6m outside the bath or shower and above the bath or shower if the child is over 2 years old 25m An IPX4 rating is required.

Zone 3: Anywhere that is not in zones 0, 1, or 2. When water jets are not to be used for cleaning, the general BS7671 rules apply. Refer to the I for more information. E E Regulations for wiring (BS 7671: 2001 Section 601)

For the most recent information, E E Regulations can be found at www.theiet.org. (Opens in a new tab)

Can I Rewire My Own House?

The Building Regulations Part P: Electrical Safety covers do-it-yourself electrical work, rewiring, and alterations to electrical installations. Minor additions or alterations to existing circuits, such as adding a new socket or light fitting, do not require a Building Regulations application if they are not in a wet area, such as a kitchen or bathroom, outdoors, or directly connected to the consumer unit. Repairs, replacements, and maintenance are not reportable.

You can still do other rewiring work yourself, including in wet areas. However, you must submit a Building Regulations application (currently around £150, including the inspection fee) and arrange for the work to be inspected both before and after completion by a qualified electrician registered with one of the competent persons schemes. They will inspect the work and issue a safety certificate if it complies with the regulations. Not all electricians provide this service, and many are unwilling to sign off on someone else's work. This approach poses a risk, both in terms of safety and financial viability.

Keep in mind that all cables buried in walls must run either vertically or horizontally from sockets. This is extremely beneficial to subsequent trades who may be screwing fixings into walls for curtain rails, radiators, shelving, or kitchen units. Some amateurs run cable at an angle across walls in order to save money without realizing the potential danger.

Choosing an Electrician to Do Your Wiring

The electrician's job, like many others, is divided into first and second fix.

• The first fix entails replacing all of the wiring, including circuits and back boxes for power, lighting (inside and out), shavers, hard-wired burglar alarms, smoke detectors, and doorbells, as well as telephone, television, data, speaker, central heating controls, and other hidden cabling.
• The second fix entails connecting the consumer unit, installing light fixtures, faceplates for switches and sockets, and connecting the boiler, immersion heater, and central heating controls.

Electricians typically prefer to work on a supply-and-fix basis, which means they provide both labor and materials (wiring, back boxes, and so on). ) Many electrical wholesalers will only sell to the trade for at least the first fix stage. Most electricians will be happy for you to supply your own sockets, switches, and light fittings for the second fix, but you must notify them of your intention.

Electricians typically work on a fixed price, though rates for each additional power point, switch, or light fitting are usually agreed upon. The cost will be calculated using measured rates based on how long they expect the work to take, the number of circuits, and the number of power points, light fittings, and switches.

They will also consider whether the work is a new build or extension, in which case they can simply face-fix the circuits, or a renovation, in which case they may have to lift floors and chase out plasterwork to conceal the wiring, which will require them to lift floors and chase out plasterwork. takes longer and is more expensive

To save time and money, you can try to keep costs down with a friendly electrician by prepping everything for them, such as chasing out plasterwork, lifting floorboards, and generally making access easy. As long as you and your electrician are both aware of the task division at the start of work, the competent renovator can chase plaster out to exactly where they want sockets and switches, buy the switches, sockets, and lighting, and possibly even assist with the installation.