Ryan, RM Electrical NAPIT registered electrician, South Wales
Replacing a consumer unit starts from £600 + VAT (£720 inc VAT) where the wiring behind it is sound, and it is usually a day’s work. That covers the new board with RCBO protection on every circuit, surge protection, labelling, testing, the certificate and building control being notified.
What moves it past that is what the testing finds once the old board is off. If a circuit will not pass, you are told before anything is ordered. Send Ryan a photo of your board and he will tell you what he is looking at.
What is a consumer unit?
It is the box that feeds every circuit in the house: lights, sockets, cooker, shower. Most people call it the fuse box or fuse board. Older ones have wire or cartridge fuses that you replace when one blows. Modern ones have switches, called breakers, that trip off and can be switched back on.
The modern ones also have protection the old ones never had, which is the main reason to change.
What you get for the money
- RCBO protection on every circuit. An RCBO is a breaker and an RCD in one. It cuts the power in a fraction of a second if current leaks to earth, which is what happens when someone touches something live. With one per circuit, a fault only knocks out that circuit, not half the house.
- Surge protection. It protects the wiring and everything plugged in from voltage spikes.
- A metal enclosure. Current regulations require the board to be non-combustible, so a fault inside it cannot set the cupboard alight.
- Every way labelled, so the next person who opens it knows what they are looking at.
- Testing of every circuit, a certificate, and building control notified. Replacing a consumer unit is notifiable work in Wales.
Signs you need a new one
- It has wire fuses or pull-out cartridge fuses instead of switches
- It has no RCD at all, or one RCD covering everything
- It is in a wooden or plastic box, or has a wooden back board
- It trips often and you cannot find why
- You are adding an EV charger, a heat pump or an electric shower, and there is no room or no suitable protection
- Your insurer, a mortgage survey or an electrical report has flagged it
None of these always means an emergency. An old board can be working perfectly well. It just gives far less protection than a modern one, and it is often the thing standing between you and an EV charger.
What can add to the price
Faults found during testing. When the new board goes in, every circuit is tested. If a circuit has a fault, the new protection will not hold on it. You are told what it is and what it costs to fix before anything else is done, never halfway through.
Moving the board. If it needs to move, for example out of a cupboard that is being knocked through, that adds cable and time.
No main earthing or bonding. Older houses sometimes have no earth bonding to the gas and water pipes. That has to be put right for the board to be signed off.
Consumer unit or full rewire?
If the wiring is in good condition, a new board is all you need. If the wiring is old rubber or fabric cable, or tests badly, a new board on top of it is money spent twice. A rewire includes a new consumer unit anyway. See what a rewire costs if you think that is where you are.
Questions people ask
How long does it take?
Usually a day. The power is off for most of it, and it is back on, tested, before Ryan leaves.
Do I need a new consumer unit for an EV charger?
Only if the existing one cannot take it safely. Many modern boards can, sometimes with an extra way added. An old fuse box cannot. The EV charger estimator asks about your board and prices it in if it needs doing.
Is a plastic consumer unit illegal?
No. A plastic board fitted before the rules changed in 2016 is not illegal and does not have to be ripped out. Any new board has to be non-combustible, which in practice means metal.
No prices on this page are guesses, because there are none. Ryan prices every job himself, in writing, after seeing it.