On this page
- You can tell what you have by what is behind the flap
- No law makes a homeowner replace a working fuse box
- An old board becomes a problem when it shows these signs
- What an EICR usually says about an old board
- Landlords: the EICR decides, not the age of the board
- Leave old fuse carriers alone
- If you do replace it, this is what the job involves
The short version
- No law makes a homeowner replace a working fuse box, because BS 7671 is not retrospective.
- No T or Test button on the board means no RCD, so nothing protects you against shock.
- On an EICR, a missing RCD on indoor sockets is usually a C3, and a C3-only report can pass.
- Burn marks, heat, crackling or oversized fuse wire need an electrician, whatever the board's age.
No law makes a homeowner replace a working fuse box, and age alone does not make one unsafe. The usual gap in an old board is no RCD protection, the device that guards against electric shock. An electrical inspection (an EICR) settles whether yours needs work, and landlords act on what that report says, not on the board's age.
You can tell what you have by what is behind the flap
Open the front flap, never the cover. What you see tells you roughly how old the board is and whether it protects anyone against shock.
| Board | What you see | RCD shock protection? | Typical view on an EICR |
|---|---|---|---|
| Rewireable fuses | Pull-out carriers with fuse wire inside | No | Not a defect in itself, if the fuse wire is the right size |
| Cartridge fuses | Pull-out carriers holding a sealed fuse | No | Not a defect in itself |
| Breakers only | Switches that flip off, no Test button | No | Missing RCD usually recorded as C3 |
| Split-load RCD board | Breakers plus one or two wider switches with a T or Test button | Yes, for circuits on the RCD | Usually fine if the circuits test well |
| Modern metal board | Metal case, RCD protection on every circuit | Yes | Built to current rules |
No law makes a homeowner replace a working fuse box
The wiring rules, BS 7671, are a British Standard rather than a law, and they are not retrospective. A board fitted under an older edition may not meet today's rules in every respect. Industry guidance is clear that this does not by itself make it unsafe or mean it has to be upgraded.
What changes over time is the standard for new work. These dates explain why so many London homes still have boards without RCDs:
- 2008: the 17th Edition brought in 30 mA RCD protection for most socket circuits in new work.
- 2016: from 1 January, new consumer units in homes needed a non-combustible (metal) enclosure, and RCDs now covered all sockets up to 20 A.
- 2019: the 18th Edition took effect, extending RCDs to sockets up to 32 A and to lighting circuits in homes.
- 2026: the current edition is BS 7671:2018 with Amendment 4.
Any work done today, including a replacement board, has to meet the current edition.
An old board becomes a problem when it shows these signs
Age is not the warning sign. These are:
- Burn marks, charring or heat on the board or around the fuses
- Crackling or buzzing coming from the board
- A wooden back board, cast-iron switches or a mix of different makes
- Fuses blowing or switches dropping often. Our guide to a fuse box that keeps tripping explains what that points to
- Fuse wire that is thicker than the carrier's rating, fitted after a fuse blew
- No RCD, on sockets that feed anything outdoors or sit in a bathroom
If you see burn marks, heat or crackling, switch off the affected circuit and book an electrician. Never fit thicker fuse wire to stop a fuse blowing: the fuse is doing its job.
What an EICR usually says about an old board
An Electrical Installation Condition Report gives each problem it finds a code. Industry coding guidance treats old boards more calmly than most websites do:
| Finding | Usual code | What it means |
|---|---|---|
| Rewireable fuses that protect the circuit properly | Not coded | Not a defect |
| No RCD on indoor sockets unlikely to feed outdoor equipment | C3 | Improvement recommended |
| No RCD on lighting circuits | C3 | Improvement recommended |
| No RCD on sockets likely to feed equipment outdoors | C2 | Potentially dangerous |
| Fuse wire too big for the circuit | C2 | Potentially dangerous |
| Charring or signs of excessive heat | C2 | Potentially dangerous |
Any C1 or C2 makes the report unsatisfactory. A report with only C3s can still be satisfactory. Our guide to what an EICR report means explains every code.
Landlords: the EICR decides, not the age of the board
What the regulations require
In England, the Electrical Safety Standards regulations for rented homes require an inspection at least every 5 years, and each tenant must receive a copy of the report within 28 days of the inspection.
When the board has to be dealt with
If the report records C1, C2 or FI items, the remedial or investigative work must be finished within 28 days of the inspection, or sooner if the report says so. An old board with only C3 observations does not have to be replaced to comply. Our landlord EICR service in East London covers the inspection and the report.
Leave old fuse carriers alone
Some old fuse boxes contain asbestos in the fuse carriers, usually in the flash guards behind the fuse wire. Left undisturbed and in good condition, it carries a very low risk. Fibres are released when it is disturbed, for example when a fuse is rewired or a carrier cracks.
So if your board is old, do not rewire fuses yourself. When you book an electrician, say roughly how old the board looks, so the old parts can be handled correctly.
If you do replace it, this is what the job involves
Replacing a fuse box with a consumer unit is notifiable work in England under Part P of the Building Regulations. A registered electrician tests the circuits first, fits a metal board with RCD protection, and gives you an Electrical Installation Certificate plus a Building Regulations compliance certificate.
A replacement costs from £400, typically £400–£700 including VAT. The wiring behind the board decides the final figure, and our consumer unit replacement cost guide explains why. To book a test or a quote, see our electrician service in London or call 07727 619854.
Frequently asked questions
Not on age alone. Rewireable fuses that protect their circuits properly are not coded, and a missing RCD on indoor sockets is usually a C3, which can still pass. The report fails if the inspector records a C1 or C2, such as heat damage or fuse wire that is too big for the circuit.
Look at what it uses. Rewireable or cartridge fuses mean an older board, and no Test button means no RCD. A plastic consumer unit was most likely fitted before 2016, when metal enclosures became the rule for new boards in homes.
Yes. Nothing stops a sale. A standard home survey does not test the electrics, so buyers are advised to get an EICR, and what it finds may come up when the price is agreed.
A plug-in RCD protects whatever is plugged into it, which is why safety guidance suggests one for sockets on a board without RCDs. It does not protect the fixed wiring, the lighting or anything wired in, so it is a stopgap rather than a replacement for RCD protection at the board.