Replacing an old fuse box with a modern consumer unit typically costs £350 to £750, averaging about £525, according to MyJobQuote, and does not automatically mean a full rewire. A consumer unit adds RCD protection that cuts power in milliseconds if current leaks. The work must be certified, usually by a NICEIC or NAPIT electrician.
Replacing an old fuse box with a modern consumer unit is one of the more affordable, genuinely worthwhile electrical upgrades a homeowner can do, and importantly, it does not automatically mean a full rewire. According to MyJobQuote’s consumer unit replacement cost guide, the job typically costs £350 to £750, averaging around £525, for a standalone swap.
What actually changes
An old-style fuse box, particularly one with a wooden back or rewireable fuses rather than switches, offers little to no protection against electric shock beyond stopping a circuit overloading. A modern consumer unit combines circuit breakers (MCBs), which trip automatically on a fault, with RCD (residual current device) protection, which cuts power far faster, within milliseconds, if it detects current leaking somewhere it should not, such as through a person. This is the difference that actually matters for safety, not just a cosmetic upgrade.
Do you need a full rewire as well?
Not necessarily, and this is the point that puts a lot of homeowners off unnecessarily. Upgrading the consumer unit is a standalone job when the existing wiring itself is in reasonably good condition. An electrician will check this before quoting: if the cabling behind the old fuse box is sound, you are simply paying to replace the box that everything connects to, not the wiring throughout the house.
| Consumer unit upgrade only | Full rewire | |
|---|---|---|
| Typical cost | £350 to £750 | Around £6,500 for an average 3-bed house |
| Disruption | Low, usually done in a day | High, floors and walls opened up |
| When it's enough on its own | Existing wiring is sound, just outdated protection | Wiring itself is old, damaged or unsafe |
If you are weighing this up alongside wider concerns about your home’s wiring, our guide to signs you need an electrical rewire covers the warning signs that point to the bigger job rather than a standalone consumer unit swap.
What a standard job includes
Most homes need a 10-circuit consumer unit, typically £470 to £650 fully fitted, covering removal of the old fuse box, installation of the new unit with RCD protection across the relevant circuits, testing, and certification of the completed work. If the consumer unit needs to be relocated, even by a metre or two, that is usually similar in cost to a standard replacement, since the labour involved is comparable.
Why this has to be certified work
Replacing a consumer unit is notifiable work under Part P of the Building Regulations. An electrician registered with NICEIC or NAPIT can self-certify the completed job and issue you a proper certificate, which you will be asked for if you come to sell the property. Always get the electrician to inspect the property and your existing wiring in person before quoting, rather than pricing over the phone, since the condition of what is already there genuinely affects what the job involves.
We check registration and independent reviews when we research every Top 5 list, so a page for somewhere like Central Liverpool or Newton Abbot is a fast way to find an electrician who already meets that bar.
Frequently asked questions
What's the difference between a fuse box and a consumer unit?
A fuse box is the older term, generally referring to rewireable fuses or a unit without modern RCD (residual current device) protection. A consumer unit is the modern equivalent, using circuit breakers (MCBs) and RCD protection that trips a circuit far faster in a fault or shock situation, which is a genuine safety upgrade, not just a name change.
How much does it cost to replace a fuse box with a consumer unit?
According to MyJobQuote's consumer unit replacement cost guide, this typically costs £350 to £750 including materials and labour, averaging around £525. A standard 10-circuit consumer unit, suitable for most homes, usually falls in the £470 to £650 range.
Do I need a full rewire to upgrade my fuse box?
No, not necessarily. Replacing the fuse box or consumer unit itself is a standalone job that does not require touching the cabling throughout your house, provided that existing wiring is in reasonably good condition. An electrician will check this as part of the job and flag it if the wiring itself also needs attention.
How do I know if my fuse box needs upgrading?
A wooden-backed fuse box, rewireable fuses (as opposed to switches or breakers), or the absence of any RCD protection are the clearest signs. An electrician can confirm this, and the condition of the wiring behind it, as part of an Electrical Installation Condition Report (EICR).
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About the author
Stu Clark
Stu spent over 15 years in the trades, working as a plumber before running his own plumbing and bathroom renovation company with a team of eight. He founded Top5Trades to give homeowners the kind of shortlist and straight advice you would get from someone who has actually done the work. More about us →