Age on its own is not a fault
The most common reason people are told they need a new consumer unit is that the existing one looks old. That is not, by itself, a reason. A board that was correctly installed, is undamaged, and tests satisfactorily can carry on doing its job. What decides the question is what an inspection finds, not what the cover looks like.
These are the findings that genuinely point to replacement:
- Rewireable fuses. The old BS 3036 type, where a fuse holder carries a length of fuse wire. They do not offer the protection modern circuits are designed around, and they can be re-fused with the wrong wire by anyone.
- No RCD protection where it is now required. An RCD is what disconnects quickly enough to protect a person, rather than just the cable. Most circuits in a home now need it, and older boards frequently have none at all.
- Signs of heat. Browning around terminals, a smell of hot plastic, or scorching inside the enclosure. This is the one that should not wait.
- Damage or missing parts. A cracked cover, missing blanks leaving live parts reachable, or a board that no longer closes properly.
- No spare ways. Not a safety fault, but a practical one. If you are adding a shower, an EV charger or a garden supply, a full board has to be dealt with anyway.
And these, on their own, are not reasons to replace a board: it is a few decades old, it is plastic, it is a brand nobody fits any more, or a single circuit keeps tripping. The last one is worth saying twice, because it is the most expensive misdiagnosis on this list.
What an EICR says about your board
If you have had an Electrical Installation Condition Report, the codes against the consumer unit tell you how urgent this is. They are worth understanding before anyone quotes you, because the difference between a C2 and a C3 is the difference between must and could.
| Code | What it means | Effect on the report |
|---|---|---|
| C1 | Danger present. Risk of injury now. | Unsatisfactory |
| C2 | Potentially dangerous. | Unsatisfactory |
| FI | Further investigation required. | Unsatisfactory |
| C3 | Improvement recommended. | Still satisfactory |
A report whose worst finding is a C3 is a satisfactory report. “Your board came back with C3s so it needs replacing” is not a reading of the report, it is a sales line. C3s are worth planning for; they are not an emergency, and you are allowed to say not yet.
What goes into a board fitted today
A non-combustible enclosure
Since January 2016 BS 7671 has required consumer units in domestic premises to be in a non-combustible enclosure, which in practice means steel. The change followed fires that began at loose connections inside plastic boards, where the enclosure fed the fire rather than containing it. An existing plastic board is not automatically unsafe and does not have to be changed on sight — but anything fitted now will be metal.
RCBOs, or a split-load board
A split-load board puts your circuits behind two RCDs. It meets the requirement, and it is cheaper. The drawback is what happens on a fault: everything on that side goes off together, so a faulty kettle can take the freezer and the router with it.
RCBOs put the RCD and the circuit breaker in a single device on each circuit, so a fault disconnects only the circuit at fault. It costs more. Whether that is worth it depends on your house rather than on a rule — it usually is if you work from home, have a freezer worth protecting, or would rather not lose the lights and the sockets at the same time in the dark.
Surge protection, assessed rather than assumed
Surge protection devices guard the installation and what is plugged into it against voltage spikes, from lightning to switching on the network. The 18th Edition expects the risk to be assessed and the decision recorded, rather than an SPD being fitted to everything by default or left out of everything by default. We will tell you what the assessment says for your installation.
Arc fault detection, where it earns its place
AFDDs detect the signature of an arcing fault — a loose terminal or a damaged cable arcing without drawing enough current to trip a breaker. They are recommended for socket circuits in dwellings and required in certain higher risk premises. They are not free, and they are not on every job we quote.
The paperwork the job has to produce
Replacing a consumer unit is notifiable work in Wales. That is not an optional extra or a line to be haggled off the price — it is the part that proves the work was done properly, and it is what a buyer's solicitor will ask for.
- An Electrical Installation Certificate for the work itself, with the schedule of test results behind it.
- A building regulations compliance certificate, which a registered electrician self-certifies, and which should reach you within 30 days.
If whoever changes your board is not registered, the work has to be notified to local authority building control in advance and a fee paid. Either route is legitimate; no paperwork at all is not. There is more detail on which jobs are notifiable in Wales, and how that differs from England, in what electrical work has to be signed off in Wales.
What we do
We test before we quote, and we show you what the tests found. If the board is fine we will say so, and if a circuit fault is the real problem we will find that instead. Where a replacement is the right answer, you get the board that suits the house rather than the longest options list, and the certificates come to you without having to be chased.
The related work usually sits alongside this: a full or partial rewire where the circuits themselves have come to the end, testing and inspection if you want to know where you stand first, and EV charger installation, which is the job that most often turns a board with no spare ways into a board that has to be dealt with.