Full House Rewiring in London in 2025: When to Rewire, What It Involves, EICR, and Costs

How to identify whether a London home needs a full rewire, the EICR electrical condition report, and Part P Building Regulations compliance in 2025: WHEN DOES A LONDON HOME NEED A FULL REWIRE? The most reliable answer to this question is to commission an EICR (Electrical Installation Condition Report) — see below. However, there are clear VISUAL INDICATORS that a property is likely to require a full or major rewire: OLD CONSUMER UNIT (FUSE BOARD): a METAL-CLAD CONSUMER UNIT (typically grey or brown metal box) with REWIRABLE CERAMIC FUSES (screwdriver-tightened ceramic holders with fuse wire) or CARTRIDGE FUSES rather than modern MCBs (Miniature Circuit Breakers) and RCDs (Residual Current Devices) indicates an electrical installation that is ALMOST CERTAINLY more than 25-30 years old and likely to need a full upgrade; a WYLEX or MEM consumer unit from the 1970s-80s with cartridge fuses is a clear sign of an old installation; any consumer unit WITHOUT RCD PROTECTION is not compliant with the 17th or 18th Edition wiring regulations; RUBBER-INSULATED OR LEAD-SHEATHED CABLES: if cable accessed at the consumer unit, in the loft, or in accessible wall chases appears to be: RUBBER-INSULATED (TRS — Tough Rubber Sheathed — black outer rubber sheath, textile-wrapped wires inside): this is a cable type that was used before the 1960s and is now OBSOLETE; the rubber insulation DEGRADES OVER TIME — it becomes brittle and cracks, exposing live conductors; a house with TRS cable should be considered a PRIORITY REWIRE; PVC CABLES FROM THE 1960S-70S: PVC-insulated single-core cables in steel conduit, or PVC/PVC flat twin-and-earth — this is better than TRS but is typically approaching or at end of service life (50-60 years); EARTH COLOURS: in cables before 2004, the EARTH CONDUCTOR is colour-coded as GREEN; from 2004 onwards, earth conductors are GREEN-YELLOW (harmonised with European colours); in cables from before 1977, the colours were: LIVE = red; NEUTRAL = black; earth = green (single-core) or bare (in flat twin-and-earth); from 2004: LIVE = brown; NEUTRAL = blue; earth = green-yellow; if the existing cables at a property use the OLD COLOUR CODING (red/black), the installation pre-dates 2004 and is at least 20+ years old; if they use pre-1977 colour codes, the installation is at least 47+ years old; SINGLE GANG OR DOUBLE GANG ROUND-PIN SOCKETS: extremely old style — indicates an installation of 1950s or earlier origin; LACK OF RCD PROTECTION: ANY modern installation must have RCD PROTECTION on all circuits in a domestic property (required by the 17th Edition 2008 onwards); if the consumer unit does not have RCDs, the installation is non-compliant; EARTHING AND BONDING DEFICIENCIES: no main protective bonding to gas or water service entry; no supplementary bonding in bathrooms (required by 16th Edition onwards); WHAT IS AN EICR (ELECTRICAL INSTALLATION CONDITION REPORT)? An EICR is a FORMAL INSPECTION AND TEST of the electrical installation at a property, carried out by a QUALIFIED ELECTRICIAN (typically an ECS (Electrotechnical Certification Scheme) or equivalent qualified person); the EICR tests and visually inspects: the CONSUMER UNIT (fuse board — condition, type, RCD provision, circuit labelling); each CIRCUIT (lighting circuits, power circuits, cooker circuit, shower circuit, immersion circuit, external circuits — EV charger, etc.); EARTHING AND BONDING (main protective bonding at gas and water entry, supplementary bonding in bathrooms); SAFETY DEVICES (RCDs tested for correct trip time, circuit breakers tested); VISUAL CONDITION OF ACCESSIBLE WIRING (identified damage, degraded insulation, incorrect connections); THE EICR CLASSIFICATION CODES: C1 (DANGER PRESENT — requires immediate action); C2 (POTENTIALLY DANGEROUS — urgent remedial work required); C3 (IMPROVEMENT RECOMMENDED — not immediately dangerous but upgrade recommended); FI (FURTHER INVESTIGATION REQUIRED — a concealed issue that cannot be confirmed by visual inspection and testing alone); LANDLORD EICR REQUIREMENT: since APRIL 2021, all PRIVATE RENTAL SECTOR (PRS) properties in England must have a valid EICR carried out by a qualified electrician at least EVERY 5 YEARS; the landlord must provide a copy to the tenant before they occupy the property and to the local authority within 28 days of request; RECOMMENDATION PERIOD FOR DOMESTIC PROPERTIES (OWNER-OCCUPIED): the IET Wiring Regulations recommends an EICR for domestic properties at least every 10 YEARS (or on CHANGE OF OCCUPANCY); COST OF AN EICR: approximately £120-£300 for a typical 3-bedroom London house (varies by number of circuits and condition of installation); PART P BUILDING REGULATIONS AND DOMESTIC ELECTRICAL WORK: PART P of the Building Regulations (England) — Electrical Safety in Dwellings — requires that NOTIFIABLE ELECTRICAL WORK in a dwelling is either: (A) CARRIED OUT BY A MEMBER OF A COMPETENT PERSON SCHEME (NAPIT, NICEIC, Stroma, etc.) — who self-certifies the work to the local authority; OR (B) SUBJECT TO A BUILDING NOTICE or FULL PLANS APPLICATION to the LOCAL AUTHORITY BUILDING CONTROL — who then inspects and approves the work; WHAT IS NOTIFIABLE WORK UNDER PART P? A full rewire of a house IS notifiable; new circuits from the consumer unit are notifiable; consumer unit replacement is notifiable; new circuits in kitchens, bathrooms, or outside (garden circuits) are notifiable; WHAT IS NOT NOTIFIABLE UNDER PART P? Like-for-like socket or light switch replacement (same position, same type — not an additional circuit); repair or maintenance work (replacing a broken socket outlet, replacing a damaged cable section in a like-for-like repair); QUALIFIED ELECTRICIANS ON COMPETENT PERSON SCHEMES: when a qualified electrician on a competent person scheme (NICEIC, NAPIT, Stroma) carries out notifiable work, they SELF-CERTIFY the work and notify the local authority on the homeowner's behalf — a PART P CERTIFICATE (Electrical Installation Certificate — EIC) is issued to the homeowner; this is the COMPLETION CERTIFICATE for the notifiable electrical work; the homeowner should keep this certificate (it is required by solicitors on sale of the property).

What a full house rewire involves in a London property, the typical programme and disruption, and realistic rewire costs in 2025: WHAT A FULL HOUSE REWIRE INVOLVES: A full house rewire in a London property involves REPLACING ALL THE EXISTING ELECTRICAL INSTALLATION BACK TO THE CONSUMER UNIT with a new 18th Edition compliant installation, including: (1) CONSUMER UNIT REPLACEMENT: removal of the old consumer unit; installation of a new DUAL RCD CONSUMER UNIT or RCBO CONSUMER UNIT (consumer unit with individual RCBO protection on every circuit — better discrimination; if one circuit trips, other circuits are unaffected); the new consumer unit must comply with BS EN 61439-3 and be installed to 18th Edition requirements; location: typically in an under-stairs cupboard, hallway, or kitchen — accessible but not in a bathroom; DUAL RCD vs RCBO: a DUAL RCD consumer unit (two banks of MCBs protected by an RCD each) is cheaper but trips an entire bank if any fault occurs on that bank; an RCBO consumer unit (individual RCBO on every circuit) provides better protection and discrimination; RCBO units are now the preferred solution for new installs; (2) NEW CIRCUIT LAYOUT: the electrician designs the circuit layout for the property: LIGHTING CIRCUITS: typically one per floor (or one per zone in a larger property); LED lighting (and EV charger loads) are now the standard design consideration; RING FINAL CIRCUITS (POWER): traditionally, a house uses RING FINAL CIRCUITS for the power sockets — the ring starts and ends at the consumer unit; modern best practice is moving toward RADIAL CIRCUITS (star topology) for simpler fault-finding and better protection; but ring finals remain acceptable under 18th Edition; KITCHEN CIRCUIT: a dedicated circuit for the kitchen (32A ring final or 20A radial + fridge, dishwasher on a separate circuit if required); COOKER CIRCUIT: dedicated 6mm twin-and-earth cable, 32A or 45A MCB; SHOWER CIRCUIT: dedicated 10mm twin-and-earth cable, 40A or 45A MCB; IMMERSION CIRCUIT (if applicable): 2.5mm twin-and-earth, 16A MCB, with 20A DP switch; OUTSIDE / GARDEN CIRCUITS: any external circuits (garden lighting, power in an outbuilding, EV charger) require RCD protection and weatherproof sockets; EV CHARGER (if applicable): dedicated circuit from consumer unit (typically 7kW = 32A, 6mm cable); requires EV-specialist installation (OZEV-approved installer for OLEV grant eligibility); (3) CABLE INSTALLATION: ALL NEW PVC-INSULATED PVC-SHEATHED (FLAT TWIN-AND-EARTH) CABLES to BS 6004 or BS 7211 (thermoplastic or LSOH — Low Smoke and Halogen Free) — new cable to every point in the installation; CABLE SIZES: lighting 1.0mm² or 1.5mm²; power ring finals 2.5mm²; kitchen/shower/cooker as above; CABLE ROUTING IN A LONDON VICTORIAN TERRACE: in a solid wall property (Victorian terrace), cables are routed in CHASES (channels cut into the masonry) — the cable is fixed in the chase and then the chase is plastered over before decoration; in a new build or recent extension with stud walls, cables can be routed through the void in the stud wall; in a LATH AND PLASTER or PLASTERBOARD PARTITION, cables can be threaded through a drilled hole between joists or via a conduit in the partition void; CHASING: cutting cable chases into solid brick or block walls GENERATES SIGNIFICANT DUST AND DEBRIS — this is a key source of disruption during a rewire; horizontal chases are limited in depth by Building Regulations (no deeper than 1/3 of the leaf thickness horizontally in a cavity wall — different rules for solid wall); (4) SOCKET, SWITCH, AND OUTLET INSTALLATION: new socket outlets (typically flat-plate white or brushed steel — CLIENT-SUPPLIED in most specifications); new ceiling roses and pendant fittings (CLIENT-SUPPLIED under standard RCB terms); USB sockets, TV coax outlets, data outlets (as specified); (5) EARTHING AND BONDING: new main earth conductor to the MET (Main Earthing Terminal) at the consumer unit; new main protective bonding conductors (10mm² green-yellow) to the gas supply entry and to the water supply entry at the internal stop valve (required by 17th/18th Edition); new supplementary bonding in bathrooms (if an older installation without supplementary bonding — supplementary bonding may now be replaced by RCD protection of the bathroom circuit per 17th Edition Amd 3); (6) TESTING AND COMMISSIONING: full INSTALLATION TEST before energising (insulation resistance test, continuity test, earth loop impedance, RCD test); ELECTRICAL INSTALLATION CERTIFICATE (EIC) issued on completion; PROGRAMME AND DISRUPTION FOR A FULL REWIRE IN A LONDON PROPERTY: A FULL REWIRE IS THE MOST DISRUPTIVE OF ALL FIRST-FIX TRADES — it requires: ACCESS TO EVERY ROOM in the property (to replace sockets, switches, light fittings); CHASING INTO THE WALLS at every socket and switch position (in a solid-wall property); ACCESS TO THE CEILING AND FLOOR VOIDS (to run the new cables between floors and to light fittings); for this reason, A FULL REWIRE IS BEST DONE AS PART OF A FULL RENOVATION (when the plaster is to be stripped anyway, and the floors are lifted for drainage and insulation works); a REWIRE CARRIED OUT IN AN OCCUPIED PROPERTY WITH EXISTING DECORATION AND FINISHES requires: more careful cable routing (chasing must be limited and repaired after); dust protection for all furnishings and belongings; scheduling floor-by-floor or zone-by-zone to maintain some liveable space; PROGRAMME FOR A FULL REWIRE (FIRST FIX + SECOND FIX) FOR A 3-BEDROOM LONDON HOUSE: FIRST FIX (chasing, cable installation, back boxes): approximately 5-10 days (in an empty property during full renovation); PLASTERING STAGE: takes place after first fix is complete (the chases are plastered, new plasterboard is fitted, all cables are buried before plastering); SECOND FIX (fitting sockets, switches, light fittings, commissioning): approximately 3-5 days after plastering is complete; TOTAL ON-SITE PERIOD: approximately 2-3 weeks (split across first fix and second fix, with the plasterer in between); REALISTIC COSTS FOR A FULL REWIRE IN A LONDON HOME IN 2025 (LABOUR ONLY — MATERIALS INCLUDED IN LABOUR QUOTE TYPICALLY FOR CABLES AND CONSUMER UNIT; SOCKETS AND LIGHT FITTINGS CLIENT-SUPPLIED): 1-BEDROOM FLAT (6-8 circuits, 30-40 outlets): approximately £3,500-£5,500; 2-BEDROOM HOUSE OR FLAT (8-12 circuits, 40-60 outlets): approximately £5,000-£8,000; 3-BEDROOM HOUSE (12-16 circuits, 60-80 outlets): approximately £7,000-£11,000; 4-BEDROOM HOUSE (16-20 circuits, 80-100+ outlets): approximately £9,000-£14,000+; NOTE: these are full rewire costs INCLUDING NEW CONSUMER UNIT, ALL CABLES, BACK BOXES, AND LABOUR — but EXCLUDING SOCKET OUTLETS, SWITCHES, AND LIGHT FITTINGS (which are typically client-supplied under standard RCB terms); PART P CERTIFICATION: included in the electrician's scope for a competent person scheme member (no additional Building Control fee if carried out by an NICEIC/NAPIT registered electrician); EICR (PRE-WORK): approximately £120-£300; what drives rewire cost higher: number of circuits; number of outlets (the more sockets and switches, the more chasing and cable routing); solid wall chasing (slower than stud wall cable routing); access difficulty (tight roof void, deep floor void, restricted access in period property); presence of old asbestos-containing materials adjacent to wiring routes (if Artex ceilings must be left undisturbed, cable routing more complex); split occupation (one floor occupied, one not — more disruption management cost).