Most London Victorian and Edwardian properties that have not been fully rewired within the last 25 years are operating on an electrical installation that no longer meets current standards. A full rewire is one of the most disruptive — and most necessary — elements of a serious renovation.
The electrical installation is invisible in a finished property but foundational to everything else. In London period properties, it is also frequently inadequate. This guide explains what a full rewire involves, how it fits into the renovation sequence, and what to consider for a high-specification contemporary installation in a period building.
When is a rewire necessary?
A full rewire should be considered when:
- —The installation has not been updated within the last 25–30 years
- —The property has rubber-insulated or lead-sheathed wiring (pre-1960s installations)
- —The consumer unit contains rewirable fuses rather than MCBs and RCDs
- —There are insufficient sockets for modern use (a Victorian house with one or two sockets per room is not adequate for contemporary occupation)
- —The property is being substantially renovated and walls, floors, and ceilings are being opened up in any case
- —An EV charging point, heat pump, or other high-draw appliance is being added
The trigger for rewiring during a renovation is not purely safety — though safety matters — it is practicality. Once plasterwork is being stripped and floors are being lifted, the marginal cost of rewiring is far lower than returning to the same works later. Rewiring after decoration is complete means chasing channels, making good, and redecorating again.
What a full rewire involves
Scope of works
A full rewire in a London period property typically covers:
- —Removal of all existing wiring back to the consumer unit
- —Installation of a new consumer unit (distribution board) compliant with BS 7671:2018 (IET Wiring Regulations, 18th Edition) — typically located in a ground floor cupboard or utility area
- —New ring main circuits for power sockets on each floor
- —New radial circuits for kitchen appliances (oven, hob, fridge, dishwasher, washing machine)
- —Lighting circuits for each floor
- —Bathroom and en-suite circuits with RCD protection and appropriate IP-rated fittings
- —Garden and external circuits
- —Data and AV infrastructure (see below)
- —EV charger circuit if required
The installation sequence in a renovation
Electrical first fix — the running of cables before walls are plastered and floors are boarded — must happen before plastering. The sequence is:
- 1.Strip plaster / lift floors (as part of renovation first fix)
- 2.Electrical first fix: run all cables, install back boxes for sockets and switches, mount consumer unit
- 3.Mechanical first fix (plumbing, heating pipes)
- 4.Insulation and plasterboard / plaster
- 5.Second fix: fit sockets, switches, light fittings, consumer unit connections
- 6.Testing and certification (EICR)
Disrupting this sequence — attempting electrical work after plastering — results in surface-run conduit, unnecessary making good, and a poor finish. In a serious renovation, this is not acceptable.
Cable routing in period properties
Period properties present specific challenges for cable routing:
Solid masonry walls: cables must be chased into the plaster or masonry and plastered over, or run in surface conduit (only acceptable in service areas). Chasing should follow vertical and horizontal routes only, per Part P of the Building Regulations, to facilitate future safe working.
Suspended timber floors: cables can be run through floor voids between joists. Where cables cross joists, drill at the centre of the joist depth (not close to the top or bottom edge where floor fixings are most likely to penetrate).
Lath and plaster ceilings: these are fragile and valuable in period properties. Cables can be run through ceiling voids above, or surface-run and plastered over where the ceiling is being replaced. Avoid chasing lath-and-plaster ceilings wherever possible.
Designing for contemporary use in a period property
A rewire is the opportunity to design the electrical installation for contemporary occupation, not simply to bring the existing layout up to standard.
Socket provision
Contemporary households use far more sockets than Victorian buildings provided for. A realistic specification for a period London townhouse:
| Room | Recommended double socket count |
|---|---|
| Main bedroom | 6–8 (including USB-A/C outlets) |
| Secondary bedroom | 4–6 |
| Living / reception room | 8–10 |
| Kitchen | 10–14 (worktop level plus appliance circuits) |
| Study / home office | 8–10 (plus dedicated data outlets) |
| Hallways | 2 (cleaning equipment) |
Underspecifying sockets is one of the most common regrets clients express after a renovation. The cost difference between 4 and 8 sockets in a room at first fix stage is marginal. The cost of adding sockets after decoration is significant.
Lighting design integration
The electrical installation should be designed in conjunction with the lighting design. This means:
- —Ceiling rose and pendant positions agreed before first fix
- —Recessed downlight positions marked on drawings before plasterboarding
- —Wall light positions wired out before plastering
- —Dimmer-compatible wiring (neutral return to switch) specified from the outset if smart or dimmer switches are planned
- —Separate lighting circuits per zone to allow independent control
Smart home and AV infrastructure
If any smart home technology is planned — lighting control, AV distribution, security, CCTV, or audio — the cabling infrastructure must be installed at first fix. Retrofitting data, control, and AV cabling after plastering is expensive and often compromises the finish. See our smart home technology guide for detail on the infrastructure requirements.
As a baseline for a high-specification London property, CAT6A data cabling to all principal rooms is worthwhile even if no active network equipment is planned immediately. The incremental cost at first fix is low.
EV charging
An EV charger requires a dedicated 7kW (32A) radial circuit from the consumer unit. OZEV-approved chargers must be installed by an approved installer. If an EV charger is anticipated, run the circuit during the rewire even if the charger itself is not yet being installed — the consumer unit position should be chosen with this in mind.
Part P and Building Regulations notification
Electrical work in a dwelling is notifiable under Part P of the Building Regulations. The approved route for compliance is to use a contractor registered with a competent persons scheme (NICEIC, NAPIT, ELECSA). The registered contractor self-certifies their work and notifies the local authority on the client's behalf. The client receives an Electrical Installation Certificate (EIC) at completion.
Where an unregistered contractor carries out the work, the local authority must be notified before work begins, and an approved inspector must inspect and certify the installation. This route is slower and more expensive; in practice, virtually all residential electrical work in London is carried out by registered contractors.
Listed buildings
Electrical installations in listed buildings are not directly regulated by Listed Building Consent — electrical works are generally considered reversible and do not affect the character of the listed fabric. However, the method of cable routing must avoid damage to original fabric: chasing original Victorian plasterwork in a listed building is problematic, and surface-run conduit in service areas or behind fitted furniture is often the appropriate approach.
New consumer units, switch plates, and socket outlets in visible positions in listed buildings should be specified with the interior character in mind. Unlacquered brass, bronze, or nickel switch plates suit period interiors; standard white plastic does not.
Our approach
ASAAN coordinates electrical rewires as part of the full renovation programme. Our electrical contractors are NICEIC-registered and experienced in the specific constraints of London period properties. The installation is designed in coordination with the lighting designer, the AV and smart home specification, and the interior design — not specified in isolation.
If you are planning a renovation that includes a rewire, contact us to discuss. Related reading: our smart home technology guide covers AV and control cabling in detail, and our renovation timeline guide covers how electrical works fit into the overall programme.
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