The short answer
A new fuse box (now usually called a consumer unit) replaces the board that protects and distributes power around your home. A full rewire replaces the cables behind the walls, floors and ceilings, usually along with sockets, switches and the board. If your wiring is in sound condition and only the board is old, a new fuse box is the sensible, cheaper fix. If the cables themselves are worn, damaged or outdated, a new board only treats the symptom and a rewire is the better choice. An electrical inspection is the way to find out which applies to your home.
How they differ
Fuse box replacement is work on one point in the house, usually near the meter. The electrician disconnects the old board, fits a new consumer unit, reconnects the existing circuits and tests everything. A modern unit includes protection that older fuse boxes often lack, such as RCDs, which cut the power quickly if there is a fault that could give someone a shock. Most of the work happens in one place, so disruption is limited. It is often finished in a day, though the power will be off for much of that time.
A house rewire is a much bigger job. Old cables are removed or abandoned and new circuits are run to every socket, light and appliance. That means lifting floorboards, cutting channels into plaster and drilling through joists. Rooms are disturbed, and decorating usually has to be redone afterwards. Some homes can be rewired in stages, room by room, while people carry on living there. Others are easier to do when empty.
The two jobs also have different aims. A new board improves protection and makes the system easier to manage. A rewire renews the infrastructure that carries the electricity, including its capacity, layout and insulation.
Cost: what makes each more or less expensive
A fuse box replacement costs far less than a rewire, because it involves less labour, fewer materials and almost no making good. The real prices homeowners paid are shown elsewhere on this page, so use those as your guide. In general terms, these factors push a consumer unit job up or down:
- The number of circuits that need connecting.
- Whether the meter and the board are in an awkward place, such as under the stairs or in a tight cupboard.
- Whether existing circuits need repairs or alterations before they can be connected safely.
- The brand and specification of the unit you choose.
A rewire is affected by many more things:
- Size of the property. More rooms and more circuits mean more cable and more time.
- Access. Solid floors, thick plaster, and ceilings you want to keep intact take more work than bare floorboards and an empty loft.
- Number of points. Extra sockets, lighting and outdoor power all add to the job.
- Making good. Some electricians include plastering and redecorating, while others leave you to arrange it separately. Check what a quote covers before comparing.
- Whether the house is occupied. Working around furniture and belongings adds time.
- Extra work. Earthing and bonding upgrades, or removing old cabling, can add to the total.
A rewire costs much more up front. Even so, if the wiring really is in poor condition, putting in a new board and then rewiring a few years later means paying for the board twice.
Lifespan and upkeep
A new consumer unit should last for many years with little attention, though it should be checked as part of routine inspections. Its life is limited mainly by the quality of what it is connected to. A new board on tired wiring is only as good as the oldest cable in the system.
A rewire, done properly with modern cable, is the longer-term fix. Wiring behind walls does not need regular maintenance, but it is worth having the installation inspected periodically. An electrical installation condition report (EICR) is the standard check. The inspector will give you a recommended interval, and landlords have their own legal obligations around testing. After a rewire you should receive certification showing the work was designed, installed and tested to the wiring standard, BS 7671. Keep it, because buyers and surveyors may ask for it.
Old wiring insulation can become brittle, and rubber or fabric-covered cable is a particular concern. Wiring does not fail on a set date, so the inspection result matters more than the age of the house.
When to choose Fuse box replacement
A new consumer unit is usually the better option when:
- Your fuse box is old, with rewirable fuses, a wooden backing or no RCD protection, but the inspection finds the cables in satisfactory condition.
- You are adding a circuit, such as for an electric vehicle charger or a new kitchen, and the existing board has no room or is not up to the job.
- Your electrician has tested the circuits and found only minor faults that can be corrected.
- The budget is limited and the priority is better protection quickly.
- You are selling and a buyer or surveyor has flagged the board as out of date.
It will not fix hidden problems in the cables, and some circuits may need individual attention. If the electrician tells you the board cannot be fitted safely until other faults are put right, take that seriously.
When to choose House rewire
A rewire makes more sense when:
- The inspection report says the installation is unsatisfactory and the cabling needs replacing.
- You find old cable types, scorch marks, crumbling insulation, or sockets that are warm, buzzing or discoloured.
- There are too few sockets, so you rely on extension leads, or the layout no longer suits how you live.
- You are renovating anyway, with floors up and walls being stripped. This is the cheapest time to rewire, because the disruption is already happening.
- You have bought an older property that has never been updated and want to start with a clean, certified installation.
The disruption and cost are worth accepting if the wiring is truly at the end of its life. Planning matters too. A rewire is easier to schedule before new floors, plaster and decoration go in.
Building regulations may apply to both jobs, and the work should be done by a competent, registered electrician who can certify it. Your local authority can tell you what applies to your property.
Questions to ask a tradesperson
- Are you registered with a recognised competent person scheme, and will I receive certification when the work is done?
- Can you carry out an inspection first, and will you explain the results in plain language?
- Is the wiring suitable for a new board, or would you advise a rewire instead?
- What exactly does the quote include? Is making good, plastering and redecorating covered?
- How long will the power be off, and can the work be done in stages?
- Who deals with building regulations notification, if it is needed?
- What will you do if you find a problem once the work has started, and how would that affect the price?
- What warranty or guarantee do you give on the work?
Get more than one quote, and make sure each one covers the same scope so you can compare them fairly. Then check them against the prices other homeowners have paid.