Replacing an old fuse box costs £500 for an 18th edition metal consumer unit with RCBOs and surge protection on up to 8 circuits, plus £200 to test the existing installation beforehand and £50 for the certificate — done in a day. For context, Bristol firms typically quote £800–£950 for an equivalent board fitted and certified. Same job whatever you call the box, and the naming is where this guide starts, because it's where the confusion starts.
Fuse box, fuse board, consumer unit: same thing, and here's the one that matters
Fuse box, fuse board, consumer unit, "the electric board": all the same object, the enclosure where your supply splits into circuits, each behind its own protective device. The name that matters is what's inside: rewireable fuses (fuse wire, mostly pre-1980s), miniature circuit breakers (the switches), and, on modern boards, RCDs or RCBOs that detect leakage to earth, the protection that saves people rather than just cables. A "fuse board replacement" and a "consumer unit upgrade" are the same purchase: swapping whatever you have for a modern, metal-enclosed board with RCD protection throughout.
Typical replacement cost
These are estimates, not quotes. Final costings always follow a free site inspection — and jobs often come in under the estimate, never over without you agreeing it first.
| Board fitted | Estimate | Duration |
|---|---|---|
| Test of the existing installation before any work | £200 | ahead of the day |
| 18th edition metal consumer unit — up to 8 circuits, RCBOs and SPD included | £500 | a day |
| Certificate for the new board | £50 | issued after |
RCBOs buy per-circuit protection, one fault trips one circuit instead of half the house, and it's the spec worth stretching to in any home where a tripped freezer or router genuinely costs you.
Planned upgrade vs urgent replacement
Planned: the board is old but behaving, and you're upgrading for RCD protection, a new shower circuit, or an EICR recommendation, book it at your convenience. Urgent: scorch marks or heat at the board, buzzing, a burning smell, repeated unexplained tripping, or a wooden backboard with vintage kit on it, book it this week and treat persistent burning smells as urgent: switch off at the main switch and get an electrician out the same day. The price is the same either way; the difference is how long you should be comfortable waiting.
Old board? Get the real price
Send a photo of the fuse board — the fixed replacement price usually comes back without a visit.
Why quotes change after testing: the honest caveat
A new board is only fitted onto circuits that pass testing, and modern RCDs detect faults an old fuse would sleep through. So occasionally a board change surfaces a pre-existing circuit fault on the day, and the job grows. The trustworthy version of this, and the test of your electrician, is that findings arrive as readings and prices in writing before any extra work proceeds, never as a bigger invoice at the end. Ask any quoting electrician how they handle faults found on the day; the answer tells you who you're hiring.
SPDs and AFDDs: the add-ons, and which are worth it
SPDs (surge protection) shield the electronics modern homes are full of, and one is included in every board I fit: BS 7671 expects them in most new installations for a reason. AFDDs (arc-fault detection) are the newer, dearer device, worth serious thought for sleeping-risk situations, HMOs and homes where fire escape is hard, and honest to call optional for a typical family house today.
How much does it cost to replace a fuse box?
£500 for an 18th edition metal board with RCBOs and surge protection on up to 8 circuits, plus £200 testing beforehand and £50 certification. If National Grid need to fit an isolation switch first, that's about £250. Any remedials testing reveals are quoted before they're done.
Is an old fuse box illegal?
No. There's no law compelling replacement of an old board that was compliant when fitted; there's an EICR that will code its shortcomings and an insurance industry increasingly interested in the answer. "Legal" and "what I'd have protecting my kids' bedroom circuits" are different standards.
Why did my quote go up on the day?
See above: testing found a fault the old board tolerated. The right process makes that a written, priced decision of yours; if it arrived as a surprise on the invoice instead, the process failed you.
Fuse box vs consumer unit: what's the difference?
Vintage. One's the old object, one's the modern one, and everyone means the same grey box in the hall. What you're buying in a replacement is the protection generation inside it.
Is surge protection required?
On new installations BS 7671 expects it in most cases; on a replacement board it's a strongly sensible add-on rather than an absolute mandate. At the price, fit it.
Around Bristol: consumer unit upgrades covers the job itself, booking and photos to send. Related money: rewiring costs where the cables are the real question, and EICR costs where the report came first.
