Full vs Partial Rewire: Which Do You Need?

If you have been told your home needs “a rewire”, the first thing to establish is how much of one. A full rewire replaces every cable, back box, socket, switch, lighting point and the consumer unit throughout the whole property. A partial rewire replaces only specific older or unsafe circuits — perhaps just the lighting, just the kitchen, or just the ground floor. They are very different jobs in scope, cost and disruption, and choosing the right one saves you either wasted money or a false economy. This guide explains both, sets them side by side, and shows how a proper inspection tells you which one you actually need.

The short version

A full rewire is the whole installation renewed from scratch. A partial rewire is a targeted repair of the circuits that are past their life while leaving the sound ones in place. Homes with old wiring throughout, or those being gutted for a major renovation, generally need the full job. Homes that are mostly fine but have one tired area usually need the partial one. The honest way to find out which camp you are in is an inspection that codes every circuit — more on that below.

Full rewire vs partial rewire at a glance

	Full rewire	Partial rewire
What it is	All cabling, back boxes, sockets, switches, lighting points and the consumer unit replaced throughout the property	Only specific older or unsafe circuits replaced (e.g. lighting only, kitchen only, or ground floor only)
What it covers	The entire electrical installation, brought up to current BS 7671 standards	The particular circuits flagged as end-of-life, dangerous or non-compliant
When you need it	Rubber, lead or fabric-insulated wiring throughout, an old rewireable fuse box, a pre-1980s installation never updated, or a major renovation/extension	The installation is mostly sound but one area — an old kitchen circuit, a dangerous DIY addition, a perished cable in a single run — needs replacing
Typical cost	£3,200–£4,800 (2-bed) up to £8,500–£12,000 (4-bed); 5–10 working days	Considerably less than a full rewire — you pay only for the circuits done
Legal requirement?	Not compulsory in itself, but the work must be certified to BS 7671 and notified under Part P	Same — any circuit replaced must be certified and Part P notified

What a full rewire involves

A full rewire is a substantial project and it helps to know the stages before you commit. It runs in a set sequence.

First fix. The disruptive part. The electrician lifts floorboards, chases channels into the walls to bury the new cables, and runs fresh cabling back to where the consumer unit sits. Because this means floors up, walls chased and the power off in stages, it is genuinely easier in an empty property — which is why many people move out or decant room by room while a house rewire is under way.

Second fix. With the cables in, the electrician fits all the accessories — the sockets, switches and light fittings — and installs a new consumer unit to modern standards, with the RCD protection an old rewireable fuse board never gave you.

Testing and certification. The whole installation is then tested and you are issued an Electrical Installation Certificate confirming it meets BS 7671, with the work notified under Part P of the Building Regulations. Always keep that certificate — it is your proof the job was done correctly and you will want it when you sell.

As a guide for the Billericay area, a 2-bed typically runs £3,200 to £4,800, a 3-bed £5,000 to £8,000, and a 4-bed £8,500 to £12,000, taking somewhere between 5 and 10 working days. Occupied houses, solid walls and awkward access all push those figures up; our cost guide breaks down what moves the price.

What a partial rewire involves

A partial rewire tackles only the circuits that need it and leaves the rest alone. In practice it is very often driven by an Unsatisfactory result on an EICR, which codes each circuit individually — so instead of renewing everything, you renew precisely the runs the report has flagged. That might be a single perished cable, an original lighting circuit in an otherwise updated house, or the wiring an extension was fitted with to a poor standard.

Because you only pay for the circuits actually replaced, a partial rewire costs considerably less than the full job. The circuits that stay must still be genuinely sound — this is the important caveat. If the walls come open and the electrician finds perished cabling running throughout, patching half of it is a false economy, and the sensible answer flips back to a full rewire.

Which do you need?

The deciding factor is the condition of the wiring throughout the property, not any single symptom.

When a full rewire is the answer

Go full if the installation has rubber, lead or fabric-insulated wiring throughout, or an old rewireable fuse box feeding the whole house. The same applies to a pre-1980s installation that has never been updated — insulation degrades with age, heat and movement, and once it is perished across the board there is nothing to save. A major renovation or extension is also the natural moment: if the floors are up and the walls are open anyway, doing the lot in one pass is far less disruptive than coming back later.

When a partial rewire is the answer

Go partial if the installation is mostly sound but one area lets it down — an old kitchen circuit, a dangerous DIY addition someone added over the years, or a perished cable in a single run. Here a full rewire would mean tearing out perfectly good, compliant cabling to no benefit. Renewing only the weak circuits brings the whole installation up to a safe standard for a fraction of the cost.

How to decide with confidence

The best starting point before committing to anything is an EICR. It inspects and codes the entire installation, circuit by circuit, so it tells you exactly which runs need work and which are fine — turning guesswork into a clear list. Book the inspection first, and the report itself will point you to full or partial.

This matters locally because Billericay has a lot of 1930s stock and large 1960s to 1980s estates, and much of that housing is now reaching rewire age. Some of those homes were partially updated decades ago and only need a circuit or two renewed; others still carry their original wiring throughout and are squarely full-rewire candidates. Two houses on the same road can genuinely need different jobs — which is why an inspection beats assuming. If you want to talk it through first, your local electrician in Billericay can advise on either route.

Getting a clear price

We are a NICEIC-registered and Part P approved firm working across Billericay and the surrounding Essex area, certifying all work to BS 7671. We will inspect your installation, tell you honestly whether it is a full rewire, a partial one, or simply a new consumer unit, and set it out in plain terms with no pressure either way.

If you would like a free, no-obligation written quote for a rewire or an EICR, send us the details through our online quote form and we will take it from there.