Electrical Works in London Renovations: Rewiring, Part P and EV Chargers

London's Victorian and Edwardian housing stock frequently has electrical installations that are at or beyond the end of their safe operational life. Signs that indicate a full rewire is needed:

• **Age of installation:**
• •Installations with rubber-insulated wiring (black rubber sleeving on conductors — common in pre-1960s properties): always rewire. Rubber insulation degrades and is a fire and shock risk.
• •Installations with PVC insulated wiring but no earth protection (2-core without earth — common in 1960s–1970s): typically rewire.
• •Installations 30+ years old without a recent EICR (Electrical Installation Condition Report) are likely to have significant defects.

• **Warning signs:**
• •Fuse wire fuse box (rather than MCB circuit breakers): strongly consider rewire — no RCD protection, trip function relies on consumable fuse wire
• •No RCD protection (residual current device — the safety trip that protects against shock): at minimum, RCD protection must be retrofitted even if the wiring is adequate
• •Single sockets in rooms (not enough for modern usage)
• •Extension leads used permanently throughout the house
• •Aluminium wiring in some 1960s properties: specialist advice required

• **Cost of a full rewire in London:**
• •2-bed flat: £3,500–£6,000
• •3-bed terrace: £5,000–£9,000
• •4-bed house: £7,000–£14,000
• A renovation project is the most cost-effective time to rewire — trades are on site, walls and floors are open, and the disruption of chasing cables and lifting boards is minimised within the overall project programme.

• Part P of the Building Regulations (Electrical Safety in Dwellings) requires that notifiable electrical work in dwellings is either:
• •Carried out by an electrician registered with a Government-approved competent person scheme (NICEIC, NAPIT, ELECSA, etc.) — who can self-certify their work; or
• •Notified to Building Control before and after the work, with an inspection by Building Control

• **Notifiable work under Part P:**
• •New circuits
• •Consumer unit (fuse box) replacement
• •Additions or alterations to circuits in special locations: kitchens, bathrooms, outdoors, under floors, in roof spaces

**Non-notifiable work:** Like-for-like replacement of sockets, switches, and fittings in dry rooms (not kitchens or bathrooms) is non-notifiable — any competent person can carry it out.

**Compliance certificate:** A registered electrician issues a BS 7671 electrical installation certificate (minor works certificate for small additions, full installation certificate for a complete new installation or rewire). This is the electrical equivalent of the Building Control completion certificate — it must be kept and presented on the sale of the property.

**Consumer unit regulations:** Since 2016, new consumer units installed in domestic properties in England must be housed in a non-combustible enclosure (metal consumer unit) or mounted on a non-combustible surface. PVC consumer units installed before 2016 do not need to be replaced, but any replacement unit must meet the 2016 specification.

**EV charge point installation:** From 2022, new residential buildings and buildings undergoing major renovation with car parking in England are required to install EV charge points (or cable routes for future installation). Beyond this requirement, many London homeowners are installing EV chargers proactively.

• •**Untethered smart charger (7kW):** The most popular domestic EV charger — charges a typical EV at approximately 30–35 miles per hour of charging. Cost: £700–£1,200 supply and install (net of any available OZEV grant — check current government grant availability at time of installation).
• •**Installation requirement:** A dedicated 32A circuit from the consumer unit to the garage, driveway, or car parking position. Notifiable under Part P. Must be installed by an OZEV-registered installer to qualify for any grant.
• •**Listed buildings and Conservation Areas:** External EV charger installations on listed buildings or in Conservation Areas may require Listed Building Consent or planning permission — check with the borough before installing.

**Solar PV:** Solar PV installations do not require planning permission as permitted development in most cases (including in Conservation Areas, unless on a listed building or visible from the highway on the principal elevation). A 4kWp system (approximately 10–12 panels) typically costs £5,000–£8,000 installed and generates approximately 3,200–3,800 kWh per year in London.

**MVHR (Mechanical Ventilation with Heat Recovery):** For highly insulated or airtight renovations, MVHR systems recover heat from extracted air and transfer it to incoming fresh air. They are increasingly specified in high-quality London renovations alongside significant fabric improvement. MVHR requires dedicated ductwork first-fixed during the renovation. Cost: £4,000–£9,000 installed for a whole-house system.

**EV charger and solar PV interaction:** Solar PV generation that exceeds current usage can be diverted automatically to charge an EV (via a solar divert feature on modern smart chargers) or stored in a battery. For homes with both solar PV and an EV, this combination significantly reduces transport fuel costs.