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Installations & upgrades

Electrical installations and rewiring

Installation work runs from adding a few sockets to rewiring a whole property. A rewire or a new installation follows a set order: positions agreed, cables run and boxes fixed while walls and floors are open, sockets and switches fitted once the surfaces are finished, then the new work inspected, tested and certified.

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You receive
An Electrical Installation Certificate, or a Minor Works certificate for an addition to an existing circuit
Agreed first
Socket, switch and light positions, before any cable is run
Two stages
First fix before plastering, second fix after it

  1. A box for each socket and switch is fixed at the position and height agreed at the survey, before anything is covered up.

  2. Each cable runs straight up, down or across to the box it serves, not diagonally, so its route can be worked out later.

  3. Between the two electrical visits, the wall is plastered over the cables, leaving the boxes open. This is normally done by your builder or plasterer.

  4. Once the walls are finished, sockets and switches are connected and fitted to the boxes, and the new work is inspected and tested before it is put into use.

  5. After plastering, the cables (dashed) still run in line with each accessory. The shaded bands show where cables may be, so avoid drilling directly above, below or beside a socket or switch. Older wiring may not follow these routes.

  6. A cable may also cross the wall within 150 mm of the ceiling, or run down it within 150 mm of a corner: the shaded band along the top and the strip beside the corner. BS 7671 sets out these zones for cables buried in walls.

Fig. 1 — First fix on the left, before plastering; second fix on the right, with the hidden cable routes dashed and the zones where cables may run shaded (Illustration)

Sound familiar?

Reasons people ask for installation work

The order matters because the first fix decides where every cable goes. Once a wall is plastered, moving a socket means cutting into it again, and anyone drilling into that wall later can only judge where cables are likely to be if they follow the recognised routes. The drawing shows one wall at both stages.

A burning smell, scorch marks, a socket that feels hot or a circuit that keeps tripping should not wait for a planned rewire. Stop using the socket or appliance concerned if you can do so safely, do not keep resetting a device that trips again, and have it looked at first. Urgent electrical problems.

  • A condition report has recommended a rewire, or recorded problems that a repair alone will not solve
  • You are renovating, and floors, walls or ceilings will be opened up anyway
  • There are too few sockets, so extension leads and adaptors are in permanent use
  • A new kitchen, utility room or home office needs more sockets or more capacity than the existing circuits have
  • You are planning an electric shower, a cooker or another heavy load, which normally needs a dedicated circuit
  • An electrician has identified older cable, such as rubber-insulated cable, which is normally replaced rather than extended
  • Rooms are being reconfigured, combined or changed in use, so the wiring no longer matches the layout

Who this helps

  • Homeowners

    Renovating, rewiring after an inspection has recommended it, or adding circuits and sockets to suit how the rooms are now used.

  • Landlords and managing agents

    Rewires and upgrades planned for the gap between tenancies, when rooms can be emptied and floors lifted.

  • Buyers of older properties

    Turning an Electrical Installation Condition Report (EICR) or a surveyor’s comment into a plan of work before you move in or start other work.

  • Businesses

    Extra circuits and power positions when an office, shop or workshop is reorganised or takes on new equipment.

The stages

The stages of a rewire or new installation

The electrical work is done in two main stages, with other trades in between. Knowing the order helps you book your builder and plasterer, and plan when each room can be used.

  1. Survey and positions

    Positions for sockets, switches, lights and any fixed equipment are agreed and marked, and the circuits planned. This is the cheapest point to change your mind.

  2. First fix

    Floorboards are lifted where needed, walls are chased or opened, cables are run and back boxes fixed. The rooms affected cannot be used normally until the walls are closed up.

  3. Plastering and making good

    Chases are filled and walls plastered or boarded, leaving the back boxes open. It falls between the two electrical stages and is for your builder or plasterer unless your quote includes it.

  4. Second fix, testing and certificate

    With the surfaces finished, accessories, light fittings and the consumer unit are connected. The new work is inspected and tested before it is put into use, and the results go on your certificate.

Step by step

How the work is done

Before we quote

Adding a socket or extending a circuit can sometimes be priced from photos: the room, the nearest existing socket, and the consumer unit with its cover left on. A rewire or a new installation needs a visit to the property.

At the visit we look at whether the existing installation can take what you want to add, including the consumer unit, the earthing and the size of the incoming supply, and at how cables can be routed through the floors, walls and ceilings. It is also when positions for sockets, switches and lights are talked through.

If you will be living in the property while the work is done, say so at this stage. Which rooms are done first, and when the power will be off, affect both the price and the programme, so they are settled before the quote is written.

  1. Tell us what you want to change

    Send the property type, what you have in mind and a few photos. A previous certificate or condition report helps if you have one.

  2. Survey

    For anything beyond a small addition, we visit to look at the existing installation, the cable routes available and the positions you want.

  3. Written quote

    The quote sets out the work included. Check that it covers the number of sockets and switches, any change to the consumer unit, and who does the making good.

  4. Agree the programme

    Agree dates for the first and second fix, with time between them for plastering. If a builder is involved, the electrical visits need to fit their programme.

  5. Installation

    Cables and boxes go in first, the walls are finished, then sockets, switches, lights and the consumer unit are connected. The stages above explain each one.

  6. Testing and certificate

    The new or altered circuits are inspected and tested before they are put into use, and the results are recorded on the certificate you receive.

  7. Building control, where required

    If the work is notifiable under Part P of the Building Regulations, it has to be notified to building control. Ask us, before work starts, how your job will be notified.

Scope

What is included

Included

  • A survey of the existing installation, for a rewire or a new installation
  • Agreeing positions for sockets, switches, lights and circuits with you
  • First fix and second fix of the electrical work set out in your quote
  • Inspection and testing of the new or altered circuits
  • A certificate recording the work done and the test results

Depends on what we find

  • Whether the consumer unit, earthing or bonding needs upgrading before new circuits are added
  • Whether the incoming supply can carry the extra load; increasing it is a matter for your network operator, which owns the main fuse (cut-out) and the incoming cable
  • How much of the existing wiring can stay, if only part of the property is rewired
  • How cables can be routed, which depends on solid or hollow walls, the floor construction and loft access
  • Whether anything found once floors and walls are open, such as damaged cable, changes the work

Afterwards

  • File the certificate with the deeds or other property papers; a buyer’s solicitor, an insurer or a letting agent may ask for it
  • Note when the certificate recommends the installation is next inspected, and book it in good time
  • Landlords in England: a rented home still has to be inspected and tested at least every five years under the 2020 private rented sector regulations
  • If the work was notifiable, keep the Building Regulations compliance or completion certificate with it

Not covered by this service: Plastering, making good and decorating, unless your quote includes them; Electrical work tied to an extension, a conversion or a shop fit-out; An inspection report on its own, if you only want to know the condition of the wiring.

The paperwork you may receive

  • Electrical Installation Certificate

    New installations, rewires and new circuits.

    • What was installed and the design details
    • A schedule of test results for each circuit
    • Signatures for design, installation and inspection

  • Minor Electrical Installation Works Certificate

    Small additions and alterations that do not add a new circuit, such as an extra socket on an existing circuit.

    • A description of the work
    • Test results for the circuit that was altered
    • The signature of the person responsible

Simplified outline, not a real certificate (Illustration)

Standards and regulations

We are a NICEIC Approved Contractor, registration number 619998000, and fully insured. How to check our registration and insurance.

  • REFInstallation, inspection and testing to the current edition of BS 7671, the IET Wiring Regulations
  • REFCertification as BS 7671 requires: an Electrical Installation Certificate for a new installation, a rewire or a new circuit, and a Minor Electrical Installation Works Certificate for an addition or alteration that does not include a new circuit
  • REFApproved Document P, the government guidance on Part P (electrical safety in dwellings) of the Building Regulations in England, which explains which electrical work in homes is notifiable to building control

Questions

Questions about installations & rewiring

How do I know whether my property needs a rewire?

Not from its age, or the look of the consumer unit (often called the fuse box), alone. An old board may be connected to wiring that is still serviceable, and a newer consumer unit may have been fitted to older cable. An EICR records the condition of each circuit, which gives you a sound basis for choosing between a full rewire, a partial rewire and targeted repairs. It is worth having one before you commit.

Can we stay in the house while it is rewired?

Sometimes, but it is disruptive. A rewire usually means lifting floorboards and opening walls in most rooms, and circuits are out of use while they are replaced. Some people move out for the first fix; others have the work done in stages, a few rooms at a time. Tell us how you plan to use the house, and we can work out at the survey what is realistic.

How long will the work take?

It depends on the size of the property, how the cables can be routed, whether it is occupied, and how soon the plasterer can come in between first and second fix. Ask for an estimate of the time on site for each electrical stage when you get your quote; the overall time also depends on the other trades.

Will my walls and floors need making good afterwards?

Usually, yes. In solid walls, cables are set into chases cut into the masonry; in stud walls they run through the void behind the board. Either way, chases and access holes need filling and the surfaces finishing, normally by your builder, plasterer or decorator unless your quote includes it, so book them before the first fix starts. Where chasing is not wanted, cables can sometimes run on the surface in trunking or conduit instead.

Can extra sockets be added without rewiring?

Often, yes, if the existing circuit is in good condition, can take the extra load, and has (or can be given) the RCD protection that new sockets normally need. The circuit is checked before it is extended, because a fault on it would be carried into the new work. An addition to an existing circuit is normally recorded on a Minor Works certificate; a new circuit gets an Electrical Installation Certificate.

Will I need a new consumer unit?

In a full rewire it is normally replaced along with the circuits. For a new circuit or two, it depends on whether the existing board has space, can give the new circuit the protection it needs, such as RCD protection, and is in good condition. The survey answers that, and if a new board is needed it will be part of the quote.

Does the work need to be notified to building control?

Some does. In England, a new circuit, a replacement consumer unit and work on circuits in the space around a bath or shower are notifiable under Part P of the Building Regulations, so a rewire normally is. Notifiable work is usually notified in one of two ways: by an installer registered with a competent person scheme, or by applying to building control before the work starts. Ask us how your job will be notified when we quote.

What happens if something unexpected turns up once the walls are open?

Opening floors and walls can reveal things nobody could see at the survey, such as damaged cable, a hidden junction or a problem with the earthing. If it changes the work, it is explained and agreed with you before it goes ahead.

Often needed alongside

Read before you book

Next step

Plan your installation or rewire

The earlier the electrical work is planned, the easier it is to line up first fix, plastering and second fix. Send us what you want to change and a few photos, and we will tell you whether a survey visit is needed before we quote.

What to send us

  • The property type, roughly how old it is, and the postcode
  • What you want: a full or partial rewire, new circuits or extra sockets
  • Photos of the rooms involved and of the consumer unit, with its cover on
  • Any previous certificate or condition report
  • Whether the property will be occupied, and whether a builder is involved
  • When you need the work done, and any building work it has to fit around

An enquiry is not a booking: we contact you first, and you see a written quote before anything goes ahead.

We list towns in London and surrounding areas, Kent, Essex, East Sussex and West Sussex. Check your postcode.

Call or email us for a free quote

Tell us the postcode and a little about the job. We will contact you to discuss it, and you get a written quote before any work starts. Quotes are free. Some survey or diagnostic visits may be charged: ask when you book.

Call 020 3883 1321 Email us

Our email address: support@dualcurrent.co.uk

Helpful to include

  • The postcode of the property
  • What the job is, or what is going wrong
  • Photos, if you have them, taken without removing any covers
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