If your fuse box uses rewirable fuses, has no RCD protection, trips repeatedly, or shows scorching or a burning smell, it is likely due an upgrade. A modern RCBO consumer unit protects each circuit individually and typically costs £700 to £900 fitted. An EICR beforehand finds any underlying faults so the new board goes in to a sound installation.
Your fuse box, or consumer unit, is the heart of your home's electrical system. It splits the incoming supply into separate circuits and cuts the power if something goes wrong. Older boards were built to a different standard, and many homes are still running one that no longer offers the protection a modern installation should. Below are six signs that yours is due an upgrade, and what a new board actually gives you.
What a Consumer Unit Does
The consumer unit is the grey or metal box, usually near your meter or front door, that holds the switches and protective devices for every circuit in the house. When a circuit is overloaded, short circuits, or develops a fault, the protective device on that circuit disconnects the power to keep you safe. The trouble is that protection has improved a great deal over the years. A board fitted decades ago simply cannot do what a current one does, which is why age alone is often reason enough to look closely at yours.
The Six Signs to Watch For
You do not need to be an electrician to spot most of these. If any of the following sound familiar, it is worth booking an inspection.
- Rewirable fuses: If your board has ceramic or plastic fuse holders with a length of fuse wire inside, rather than switches that flip, it is an old design. Rewirable fuses are slow to react and easy to fit with the wrong rated wire, which removes the protection entirely.
- No RCD protection: An RCD (residual current device) is the part that protects people against electric shock. If your board has no test button, it almost certainly has no RCD, and that is one of the strongest reasons to upgrade.
- Frequent tripping: A board that trips now and then is doing its job. One that trips repeatedly is telling you there is an underlying fault or an overloaded circuit that needs investigating, not just resetting.
- Scorching or a burning smell: Any browning, melting, or a hot plastic smell around the board is serious. Switch off if you can do so safely and call an electrician straight away. This is not something to leave.
- No room for new circuits: Adding an EV charger, an electric shower, or a garden supply needs a spare way on the board. If yours is full, an upgrade is usually the sensible route rather than bolting on extras.
- An old or unknown-age board: If you have recently moved in, cannot say how old the board is, or it clearly dates back a few decades, an inspection will tell you where you stand. Wear, loose connections, and outdated components all build up over time.
Not Sure About Your Fuse Box?
Call Vartia Electrics on 020 8144 1428. We are a Which? Trusted Trader covering Sidcup, Bexley, and the surrounding areas, and we are happy to take a look and advise.
Call for AdviceWhy a Modern RCBO Board
The board we most often fit today is a full RCBO consumer unit. An RCBO combines overload protection and shock protection in a single device, and there is one for every circuit.
- Protection on every circuit: With a device per circuit, a fault on one part of the house only disconnects that circuit. The rest of the home stays on, so a tripped socket circuit will not plunge your whole house into darkness.
- Faster, safer disconnection: RCD protection responds to the small leakage currents that flow through a person during a shock, and disconnects in a fraction of a second. This is protection an old rewirable board simply does not provide.
- Easier fault finding: Because each circuit is protected on its own, tracing a problem is far quicker. That means less time diagnosing and a clearer picture of what tripped and why.
- Ready for the future: A modern board leaves room and provision for the things people add later, such as an EV charger or additional circuits, without a rethink of the whole installation.
Why an EICR Comes First
A new consumer unit is only as good as the wiring behind it. Fitting a modern board with sensitive RCD protection onto an installation that has hidden faults often means the new board trips the moment it is energised, because it is now detecting problems the old board never could.
That is why we usually recommend an EICR (Electrical Installation Condition Report) before, or as part of, a board change. The EICR checks the condition of the wiring, earthing, and bonding, and flags anything that needs putting right first. It means the new board goes on to a sound installation, and you are not left chasing faults afterwards. If you would like to read more about testing, see our guide to the EICR for landlords, which explains the same inspection in a rental context.
Cost Guide
A consumer unit upgrade is a fixed, planned job, and the cost depends on the size of the board and what the installation needs.
- Fuse box replacement: £700 to £900 fitted for a standard domestic board change, including the new RCBO consumer unit, the fitting, and the certification.
- EICR beforehand: £150 to £350 depending on the size of the property. This is money well spent, as it confirms the installation is sound before the new board goes on.
- Remedial work: If the EICR finds faults, the cost of putting them right depends on what is found. We explain everything and give you a clear price before any work goes ahead.
Every job is certified, and we talk you through what we are fitting and why. At Vartia Electrics there are no hidden charges, just a straight explanation of what your installation needs.
Frequently Asked Questions
Most domestic consumer unit changes are completed within a day. The power is off for part of the time while we swap the board over and test each circuit, and we let you know in advance so you can plan around it.
A rewirable fuse box is not automatically dangerous, but it offers far less protection than a modern board. In particular it usually has no RCD protection against electric shock, and the fuse wire can be replaced with the wrong rating, which removes the safeguard. An inspection will tell you where yours stands.
We strongly recommend it. A modern board with RCD protection will detect faults an old board ignored, so an EICR first confirms the wiring is sound and lets us put right anything that needs attention before the new board goes on. That avoids nuisance tripping later.
Repeated tripping usually points to a faulty appliance, an overloaded circuit, or a fault in the wiring. The board is doing its job by cutting the power, but the cause needs finding rather than just resetting the switch. If it happens often, book an inspection so we can trace it properly.
