The consumer unit is the box the incoming supply enters and the circuits leave: main switch, protective devices, and in a modern unit residual current protection for the circuits that need it. Replacing one is priced on the number of circuits and on what the earthing and bonding arrangements turn out to be, both of which are knowable before anyone quotes.
What a consumer unit does
It divides the supply into circuits and protects each one. The main switch isolates everything; the protective devices disconnect a circuit that draws too much current; residual current devices disconnect when current leaks to earth, which is the protection that matters if somebody touches a live part or a cable is cut. A unit with none of the last is the usual reason for an upgrade.
What a replacement consumer unit quote should include
The unit itself and its devices, reconnection and testing of every circuit, the installation certificate, the circuit chart, notification under Part P, and making good where the old board came off. A quote that names only the unit and the labour will meet the rest as extras, and the testing is not optional.
The variables that move it most
Circuit count. Whether the meter tails, main earthing conductor and bonding need upgrading to current sizes, which is common on older properties and is real work in its own right. Whether the position of the board has to change. And whether the supplier has to attend to pull the fuse, which is a scheduling problem more than a cost.
Why testing can add to the bill
Every circuit is tested after reconnection, and a circuit that fails cannot simply be reconnected and forgotten. Older properties turn up borrowed neutrals, damaged cables and undersized earths at this point. A good electrician warns you it is possible before starting rather than presenting it as a surprise afterwards.
Consumer unit upgrade cost against replacement
An upgrade normally means the same thing: you cannot usefully add modern protection to an old rewireable board. Where the existing unit is serviceable, adding an RCD to a single circuit or replacing a device can be a legitimate smaller job, and an inspector who suggests one rather than a full replacement is worth listening to.
Consumer unit replacement cost UK wide, and what the price is made of
Four things, and the board is the cheapest. The labour to swap the unit, which is a half to a full day depending on how many circuits and how tidy the existing tails are. The earthing and bonding, because the new unit's protective devices only work if the earthing is up to current standard and bringing it up is often the largest line. The tests and the certificate afterwards, which are not optional and take time. And the making good, since the old board rarely matches the new footprint. Anybody quoting from a photograph is quoting for the first item only.
When to replace consumer unit boards, rather than repair them
Three triggers, and age alone is not one of them. A board with no residual current protection on circuits that now require it, which is the commonest reason and often comes out of a condition report. Physical condition: a plastic enclosure where the standard now wants a non combustible one, signs of heat at the terminals, or devices no longer available as spares. And a change in use, such as adding a shower, a car charger or an outbuilding supply, where the existing board has no room and no spare capacity. A board that is old, intact, correctly protected and tested is not a fault to be fixed.
A fuse box cost, and what a quote should itemise
Whatever the board is called, the quote should separate five things so it can be compared: the board itself and the number of ways, the labour for identifying, testing and reconnecting each circuit, the earthing and bonding work if any is needed, the certification and the building regulations notification, and the rate for anything the tests turn up. A single figure with none of that behind it is a guess at somebody else's house. The two things a price almost never includes, and which are worth asking about before the day, are the distributor's attendance if the supply cannot be isolated, and remedial work on circuits that fail their tests, because neither is knowable in advance and both change the total.
Questions people ask about consumer unit replacement cost
What is a consumer unit?
The board where the electricity supply enters the property and is divided into circuits, containing the main switch and the protective devices for each circuit.
Is a consumer unit the same as a fuse box?
In everyday use, yes. Fuse box usually means an older rewireable board, and consumer unit the modern equivalent with circuit breakers and residual current protection.
Why does the earthing and bonding affect the price?
Because a new unit can only be certified if the earthing arrangement and the main bonding meet current requirements, and upgrading them is separate work.
Do I need a certificate afterwards?
Yes. Replacing the unit means testing and certifying the installation, and the work is notifiable under Part P in England and Wales.
How much to replace a consumer unit?
It turns on the circuit count, whether the meter tails, main earthing conductor and bonding need upgrading to current sizes, and what testing turns up once every circuit is reconnected, plus the installation certificate and notification under Part P.
What is the fuse box replacement cost made up of?
The unit and the labour, plus the testing the new installation needs, plus anything the tests find: earthing and bonding upgrades are the line that most often moves a quote, because a new unit cannot be signed off on an installation that does not meet them.