Full House Rewire: When You Need One, What's Involved & Typical Timelines

Summary

A full house rewire replaces all fixed electrical wiring — from the consumer unit through to every socket, switch, light fitting, and fused spur. It is among the most disruptive but also most necessary maintenance tasks for older UK properties. Many homes built before 1970 still have their original wiring, which may be rubber-insulated, lead-sheathed, or wired in round-pin sockets — all of which are past safe service life.

The trigger is usually a failed periodic inspection (Electrical Installation Condition Report, or EICR) or a property sale where the buyer's survey flags old wiring. A C1 finding (danger present) or a pattern of C2 findings (potentially dangerous) in an EICR is strong evidence that a rewire is justified rather than piecemeal repairs.

Rewires are almost always Part P notifiable work — a new set of circuits throughout the house constitutes a new installation, not maintenance. This means using an electrician registered with a competent person scheme (NAPIT, NICEIC, SELECT in Scotland) or separately notifying building control. At completion, a full test and an Electrical Installation Certificate (EIC) must be issued.

Key Facts

• Age threshold — Wiring over 25 years old should be tested; over 40 years old (pre-1985) almost always needs replacing
• Rubber insulation — Pre-1965 rubber-insulated cable becomes brittle and cracks; a major fire and shock risk
• PVC wiring life — PVC-insulated cable installed to good standards can last 25-40 years
• Old colours — Pre-2004 colour code: red (live), black (neutral), green (earth); changed to brown/blue/green-yellow in 2004
• Rewire notification — Full rewire is notifiable work under Part P; must be certified on completion
• Consumer unit upgrade — A rewire always includes a new consumer unit with RCBOs or dual-RCD split-load protection
• Circuit count (typical 3-bed) — 12-18 circuits: upstairs lighting, downstairs lighting, ring main (upstairs), ring main (downstairs), kitchen ring, cooker, immersion/boiler, shower, 1-2 spurs
• Cable used — Twin and earth (T&E) 2.5mm² for ring finals, 1.5mm² for lighting; larger for kitchen, shower, cooker
• Redecoration — Virtually all surfaces require making good after a rewire; walls are chased for cables
• Timescale (2-bed) — 3-4 days for wiring, plus making good
• Timescale (3-bed semi) — 5-7 days for wiring, plus making good
• Timescale (4-5 bed detached) — 7-12 days for wiring, plus making good
• First-fix and second-fix — Wiring is done in two stages: cables run and fixed first (first fix), then boards/faceplates fitted after plastering (second fix)
• Certificates — Electrical Installation Certificate (EIC) issued on completion; each circuit gets individual test records

Quick Reference Table

Detailed Guidance

Signs a Rewire Is Needed

The following are strong indicators:

1. Round-pin sockets — These predate BS 1363 and are over 60 years old
2. Rubber or cloth-covered cables — Can be spotted in the loft or where cables are exposed; rubber becomes brittle and cracks with age
3. Older fuse box with rewirable fuses — No RCD protection; old fuses may have been incorrectly rated
4. Pendant light fittings with no earth terminal — Indicates old two-core only wiring
5. Sockets with only two holes — No earth pin; dangerous and illegal for most modern appliances
6. EICR with multiple C2 findings — Potentially dangerous conditions found; rewire more cost-effective than multiple repairs
7. Sockets and switches that spark or are warm to touch — Can indicate deteriorating insulation or poor connections
8. Burning smell from sockets or switches — Immediate safety concern; investigate before rewire decision

The Rewire Process: Step by Step

Before starting:

• Customer decants rooms where possible (carpet protection if not)
• Supplier confirms and meters are accessible
• Building control notification (or competent person scheme membership confirmed)

Day 1-2 (First Fix — Wiring):

• Consumer unit disconnected and removed
• New consumer unit board position agreed and fixed
• Cables run throughout property — through joists, chased into walls, surface-run in conduit where chasing is impractical
• Back-boxes for sockets and switches installed
• All cables terminated at consumer unit end (tails left long for connection)
• Cables left unterminated at outlet ends (for plasterer to plaster over back-boxes)

Days 3-5 (Plastering and Making Good):

• Plasterer makes good all chased walls
• This is the homeowner's responsibility to arrange, or the electrician's if agreed
• Allow 24-48 hours for new plaster to dry before second fix

Second Fix (after plastering):

• Consumer unit fully wired and labelled
• All socket faceplates, switch plates, and light fittings installed
• Cooker connection unit, shower pull-cord, shaver socket, and any special circuits completed

Testing and Certification:

• Full test of every circuit: insulation resistance, continuity, polarity, earth fault loop impedance, RCD trip time
• Electrical Installation Certificate (EIC) completed
• Consumer unit circuits labelled
• Copy of EIC provided to homeowner and copy registered with competent person scheme

Consumer Unit Requirements

A modern rewire must include a consumer unit meeting BS EN 61439-3 (formerly BS 60439-3). Key requirements:

• Metal consumer unit — Required since 2016 amendment to BS 7671; plastic consumer units are no longer acceptable for new installations
• RCD protection — Either RCBOs for each circuit (most expensive but no nuisance tripping), or dual-RCD split-load (cheaper; one RCD trips half the circuits)
• Surge protection — Since the 2018 edition, BS 7671 recommends SPD (Surge Protection Device) in domestic consumer units; increasingly standard
• Circuit labelling — Every way must be clearly labelled (Regulation 514.8)

Dealing with Asbestos

Properties built between approximately 1945 and 1999 may contain asbestos. During a rewire, chasing walls and drilling through ceiling/floor voids can disturb asbestos-containing materials (ACMs). The most common ACMs encountered by electricians include:

• Artex ceiling coatings (chrysotile asbestos)
• Old insulating board in consumer unit cupboards
• Textured coatings on walls

Before starting a rewire in a property of this era, an asbestos survey should be commissioned if not already done, or at minimum a visual risk assessment carried out. See asbestos for full guidance.

Making Good

Making good after a rewire is often not included in the electrician's price. Clarify this in the quote:

• Who plasters the chased walls (specialist plasterer, or the electrical contractor)?
• Who makes good skirting boards and floorboards where lifted?
• Who redecorates?

A clear scope in the quote prevents disputes. See building control for certification requirements.

Frequently Asked Questions

How long does a house rewire take?

A typical 3-bedroom semi takes 5-7 working days for two electricians to complete the wiring. This does not include plastering, making good, or redecoration — allow at least another week for the property to be plastered and dried before second fix, then 2-3 days for second fix. Total project time from start to habitable: 3-4 weeks for a typical house.

Do I need to move out during a rewire?

You don't have to, but it's highly recommended for rooms being worked on. Electricians need to access every room, and dust from chasing is significant. Many customers stay with family for the wiring first fix, then return when basic power is restored at the end of each day. At minimum, expect loss of power for parts of each day and significant disruption.

What's the difference between a rewire and a consumer unit upgrade?

A consumer unit upgrade replaces only the fuse board and adds RCD/RCBO protection to existing circuits. It doesn't replace any of the wiring itself. This is appropriate when wiring is in good condition (confirmed by EICR) but the fuse board is old. A full rewire replaces everything — the consumer unit plus all the wiring back to each outlet. If an EICR shows the wiring itself is degraded, a consumer unit upgrade won't fix the underlying problem.

Can I live in the house while one room at a time is rewired?

Yes, in theory — this is sometimes called a "phased rewire." In practice it costs more, is more disruptive over a longer period, and makes making good harder because you're never finishing a complete room. Most electricians will advise against it unless there's a strong reason (for example, a commercial property that can't close completely).

Regulations & Standards

• BS 7671:2018+A2:2022 — IET Wiring Regulations; the governing standard for all UK wiring work

• Part P of the Building Regulations — New electrical installation in a dwelling is notifiable work

• BS EN 61439-3 — Standard for distribution boards (consumer units); requires metal enclosures since 2016

• Building Regulations Approved Document P — Guidance on electrical safety in dwellings

• Electrical Installation Certificate (EIC) — Required on completion of new installation; defined in BS 7671 Appendix 6

• NICEIC Rewiring Guidance — Guidance from one of the UK's main competent person schemes

• IET Guidance Note 3: Inspection and Testing — Testing methodology for installation verification

• Electrical Safety First — Consumer guidance on rewiring and electrical safety

• consumer units — Consumer unit standards and selection

• part p notifications — When Part P notification is required

• competent person — Competent person schemes for self-certification

• asbestos — Asbestos awareness for rewires in older properties