The consumer unit (what most people still call the fuse box) is the heart of your home's electrics. Every circuit runs through it, and every protective device that stands between a fault and a fire or an electric shock lives inside it. A lot of London homes are still running on boards that were fitted decades ago: rewirable BS 3036 fuse boards, or early breaker boards with no RCD protection at all.
An old board does not automatically mean danger, but it lacks the protection modern boards provide. RCDs and RCBOs disconnect a circuit in milliseconds when current leaks to earth, which is what saves lives when someone drills into a cable. Rewirable fuses just melt, eventually.
We replace consumer units across Greater London to the current edition of BS 7671, usually with individual RCBOs per circuit. The work is notifiable under Part P of the Building Regulations, and you receive an Electrical Installation Certificate with full test results on completion.
What's included
Pre-work inspection and testing
A new board on top of faulty wiring fails its commissioning tests, so we check earthing, bonding and insulation resistance before we quote and flag any problems up front.
A modern metal consumer unit
We fit metal-clad boards as required by BS 7671, normally with an RCBO on every circuit rather than shared dual-RCD banks, so a fault in the kitchen cannot take out the freezer, the router and the lights together.
Surge protection (SPD)
New boards include a surge protection device, which protects electronics, boilers, EV chargers and smart home kit from voltage spikes on the network.
Earthing and bonding brought up to standard
We check the main earthing conductor and the bonding to gas and water pipework, and upgrade them where undersized. This is a condition of energising a new board, not an optional extra.
Full testing and certification
Every circuit is dead tested and live tested, results are recorded, and you get an Electrical Installation Certificate plus Building Regulations notification for the Part P record.
How the job runs
- 1
Enquiry and photos
Send us a photo of your current board and meter position. That tells us the board type, earthing arrangement and circuit count, and lets us give a realistic price range straight away.
- 2
Survey and fixed quote
We visit, test the key circuits, check earthing and bonding, and give you a fixed written price. If anything needs fixing before a board change makes sense, you hear about it now, not on the day.
- 3
Installation day
A straightforward board change takes most of a day. Power is off for several hours while we strip the old board, fit and terminate the new one, and correct any tired terminations we find.
- 4
Testing and energising
Every circuit gets the full sequence of dead and live tests before we energise. Anything that fails is investigated and put right rather than glossed over.
- 5
Certification and handover
You receive the Electrical Installation Certificate with test results, the Building Regulations notification follows, and we walk you round the new board so you know what every device does.
What it costs
Consumer unit replacement starts from £550, and most London jobs land between £550 and £900. The price moves with the number of circuits (a one-bed flat with six ways is quicker than a house with fourteen), the board specification (full RCBO boards cost more in parts than dual-RCD boards), and the condition of what we find.
The most common extras are upgrading undersized earthing and bonding and correcting faults that testing reveals. We test before we quote so those costs appear in the written price, not as surprises on the day. The price we agree is the price you pay.