Rewiring a home: what it actually involves

There comes a point where repairing circuit by circuit costs more than redoing everything. That point isn't always easy to spot, and many owners put the decision off simply because nobody has told them what to expect. So here's how a full rewiring actually runs: what comes out, what stays, how long it takes and what it costs. For the wider frame, our electrical renovation page covers the whole subject.

When to rewire rather than repair

Three situations justify a full rewiring rather than targeted fixes.

The first is no earth anywhere. If not a single circuit has a protective conductor, there's nothing to salvage: new cable has to be run throughout. Adding a residual-current device to an installation with no earth is like fitting a seatbelt to a seat that isn't bolted down.

The second is systematic undersizing: 1.5 mm² on socket circuits, insufficient cable for the kitchen, one circuit feeding half the home. Here too, patching circuit by circuit ends in redoing everything anyway — more expensively, and in several goes.

The third is the whole-property job. If walls are already open for other trades, if partitions are still to go up, this is the moment: running the electrics at that stage costs two to three times less than coming back after the finishes.

Outside those cases a targeted rework is usually enough — and our page on electrical code compliance helps you sort what's a safety matter from what can wait.

What stays and what goes

This is what moves a quote the most, and nobody mentions it: when the existing conduit is sound, we don't break the walls, we only replace the wires inside.

In practice, we tie the new conductors to the old ones and pull them through the existing conduit. It takes method — a crushed or tightly bent conduit will resist — but when it works, it changes everything: no chasing, no making good, no repainting. In a 1970s or 80s property with decent conduit, that's a substantial saving over a chased rewire.

Conversely, some things are always replaced: the panel, the accessories (sockets, switches), and any cable under timber moulding or without mechanical protection. Junction boxes buried in walls have to be made accessible or removed — the standard requires it, and it's also what will let the next job happen without reopening everything.

How the job runs

The order almost never changes.

1. Survey. We identify the existing circuits, note the points to create, and agree with you where every socket and switch goes. This is the stage where your habits matter more than the standard.
2. Strip-out. Power off, removal of the old accessories and of the cable being abandoned.
3. Running the cable. Pulled through existing conduit where possible, new routes created where not — trunking skirting, false ceiling, chasing where the substrate allows.
4. Points and accessories. Back boxes, sockets, switches, lighting points.
5. The panel. Circuit distribution, protective devices, labelling. The detail is on our electrical panel replacement page.
6. Testing. Earth continuity, tripping of every residual-current device, insulation resistance, circuit-by-circuit checks before power goes back on.

If the installation is entirely new, a Consuel certificate closes the job before the meter is reconnected.

How many circuits, and which ones

A sound installation isn't measured by its number of sockets but by its number of circuits. A three-room home usually has between twelve and sixteen: several lighting circuits, several socket circuits, and above all the dedicated circuits that each get their own line and protection — washing machine, dishwasher, oven, a 32 A hob, and the heating if it's electric.

That separation is why a fault in the kitchen doesn't darken the bedrooms, and why a faulty appliance is located in two minutes instead of an hour. When your power keeps tripping, it's almost always because that work was never done: our page on a breaker that keeps tripping explains the mechanism.

Duration, budget and living through it

Allow one to three weeks depending on the size and on whether walls have to be opened. The budget starts at €150/m² incl. VAT with standard-brand accessories, excluding making good — plaster, paint, flooring — which is priced separately.

Can you stay in the property? In most cases yes: we work room by room and restore power every evening. The kitchen and bathroom are the two sensitive points, because they concentrate the dedicated circuits; we arrange things so they're never both out at once. On a heavy renovation with the walls open, though, plan to stay elsewhere for a few days — and we tell you that before starting, not halfway through.

On budget again, the reduced 10% VAT applies to homes over two years old, and our page on electrical renovation grants covers the rest. Our electrician pricing in Paris is public, and for a precise costing, contact us: the visit is free and the detailed quote follows within a week.