Consumer Unit Replacement Cost: What a New Fuse Box Really Costs
Updated: 3 hours ago
Most straightforward consumer unit replacements in the UK fall between about £350 and £800, according to Checkatrade's June 2026 cost guide, with a typical 10-way board fitted with RCBOs at around £485 including installation (its price table lists ballpark averages plus VAT). The IET's consumer guidance gives a wider range of £500 to £2,000 for a domestic consumer unit including installation. The gap between those two ranges is mostly the extra work that only shows up once the existing circuits are tested, so the real figure for your home comes from a quote after a visit.
What drives the cost of a new consumer unit?
The board itself is rarely the expensive part. The price moves with how many circuits you have, which protective devices go in the new board, and what the electrician finds when they test the wiring that will be connected to it.
Every consumer unit replacement we price starts from the same question: will the existing circuits pass testing? A board swap on sound, well-earthed wiring is a one-day job. A board swap that uncovers a missing earth on the lighting, undersized bonding or a damaged cable behind a kitchen unit is a bigger job, and nobody can see that from a photo.
The main cost drivers, roughly in order of how often they change the figure:
Number of circuits: more circuits means a bigger board, more devices and more testing time.
Board type: a board with one RCBO per circuit costs more in parts than a dual RCD board.
Earthing and bonding: if the main earth or the bonding to gas and water pipes is not adequate, it has to be put right first.
Faults found on test: circuits that fail testing cannot simply be reconnected.
Location: moving the board, or fitting it somewhere awkward, adds labour and cable.
Typical fuse box replacement cost by home size
Checkatrade's guide breaks its averages down by property, assuming the wiring is in good condition and the board stays where it is:
Terraced house: around £350
Semi-detached house: around £550
Large detached house: around £750
By circuit count, it puts smaller homes with about six circuits from £350 and larger homes with twelve or more circuits at up to £800. Its guide price for labour on the swap itself is around £160, with a 10-way board supplied fully populated with MCBs at about £120 and one populated with RCBOs at about £250.
Treat these as the floor of a sensible budget rather than the ceiling. They describe a like-for-like swap with nothing else to fix.
RCBO board or dual RCD board: how the choice changes the quote
A dual RCD board splits your circuits into two groups, each behind one RCD. A full RCBO board gives every circuit its own combined RCD and breaker. The RCBO board costs more in parts, but a fault on one circuit only switches off that circuit rather than half the house.
We explain the layouts in detail in our guide to RCBO vs RCD, including the "high integrity" boards that sit in between. On price, the difference on a typical 10-way board is the gap between those supply-only figures above, so for most homes it is a modest share of the total.
Extras that can be added to the quote
A few items are often priced separately, and it is worth knowing which are optional and which are not.
Surge protection (SPD): in a typical home, BS 7671 now expects surge protection in new work unless the owner of the installation declares it is not required and accepts the risk. The IET's consumer guidance says an SPD may cost as little as a few hundred pounds, weighed against the value of the wiring and electronics it protects.
Arc fault detection (AFDD): these are required on socket circuits up to 32 A in higher-risk premises such as houses in multiple occupation, and recommended elsewhere, where you can choose to leave them out. The IET's consumer guidance puts a single device at around £100, so a board with several can add noticeably to the parts bill.
Earthing and bonding upgrades: Electrical Safety First's best practice guide on replacing consumer units says the installer must confirm the main earthing, the main protective bonding and the meter tails are adequate before the new board goes in. In a typical home BS 7671 calls for 10 mm² main bonding, although the guide accepts an existing 6 mm² conductor in some cases if it has been in place for years with no sign of heat damage. If these checks fail, the upgrade has to happen first.
Moving the board: Checkatrade's guide puts relocating a consumer unit at around £400, and moving it together with the incoming mains cable from the street at £2,000 or more.
What a consumer unit quote may not include
Most quotes include removing the old unit, supplying and fitting the new one, testing and the certificate. Many do not include:
repairs to circuits that fail testing
rewiring any part of the house
moving the board
making good plaster or decoration
The testing is where surprises come from. Electrical Safety First's guidance is clear that a circuit with a dangerous defect must not be reconnected to the new board until it is fixed, or it stays disconnected. Homes built before 1966 may have lighting circuits with no earth conductor, because the rules at the time did not require one, and those need a proper fix before they are reconnected. Where rubber-insulated or lead-sheathed cable is found, the same guide strongly recommends replacing the cable before changing the board, because handling old insulation during the swap is likely to damage it.
If you want a clearer picture before you get quotes, an EICR on the whole installation shows what state the circuits are in. Electrical Safety First recommends one before a planned board change, and Checkatrade's June 2026 figures put a typical EICR at about £150 for a one-bed flat up to about £375 for a five-bed house.
Why the swap has to be tested and notified
Replacing a consumer unit is notifiable work under Part P of the Building Regulations in England, set out in Approved Document P. It must be done by a registered electrician who can self-certify the work, or building control must be told before work starts.
When a registered installer does it, you should receive an Electrical Installation Certificate with the test results for every circuit, and a Building Regulations compliance certificate should reach you (and your local building control body) within 30 days of completion. Keep both: solicitors ask for them when you sell, and the next electrician will want the test results.
The work is also designed to the current edition of BS 7671, which is BS 7671:2018+A4:2026. You may see quotes that refer to Amendment 3, which the IET says remains valid until 15 October 2026.
How long does a consumer unit replacement take?
Checkatrade's guide says a standard replacement takes about 4 to 7 hours, with larger or more complex installations taking up to a full day, and longer if rewiring is needed. The power is off for most of that time, so plan around the freezer, home working and anything that needs to stay on.
How to compare consumer unit quotes
Quotes that look far apart are often pricing different jobs. Before you choose, check each one answers these points:
Does it include testing every existing circuit, and what happens if one fails?
Is the board an all-RCBO board, a dual RCD board or a mix?
Is surge protection included, or listed as an option you have declined?
Are earthing and bonding checks included, and is any upgrade priced?
Will you get an Electrical Installation Certificate and a Building Regulations compliance certificate?
A cheap quote that assumes nothing will be found is not cheaper if the extras arrive on the day. If your board is showing its age, our guide to what a consumer unit is explains what each part inside it does.
Whether you need an electrician in Telford, Shifnal or Wolverhampton, we carry out fuseboard upgrades across the wider West Midlands, and every quote follows a look at the board and the wiring behind it. If you would like a figure for your home, get in touch with SM Electrical.
Consumer unit cost questions, answered
Do I have to replace a board just because it has old fuses?
No. The Electrical Safety First guide notes that a board with rewireable or cartridge fuses does not have to be replaced for that reason alone, because those fuses can still give satisfactory protection. If it is in good condition and the circuits test well, you may not need to spend the money yet.
Can I buy the consumer unit myself to save money?
Some electricians will fit a customer-supplied board, but many will not, because they certify the whole installation and need to know the devices are compatible and correctly rated. Ask before you buy anything.
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