Short answer: yes. Replacing a consumer unit (the fuse board) is one of the few electrical jobs in England that you cannot legally carry out yourself without involving Building Control. Here is what the rules actually say, what a competent electrician does that a DIY swap misses, and what a replacement typically costs in Wallington and the surrounding Sutton and Croydon areas.
Part P of the Building Regulations applies to all domestic electrical work in England and Wales. Most small jobs, such as adding a socket to an existing circuit, are not notifiable. A consumer unit replacement is different. It is explicitly listed as notifiable work, which means the local authority must be told before or after the job and a certificate must be issued.
There are two lawful routes. The first is to use an electrician registered with a government-approved competent person scheme such as NICEIC, NAPIT, ELECSA or STROMA. They self-certify the work and notify Sutton Council on your behalf, usually within 30 days. The second is to notify Building Control yourself before starting, pay their fee (often £250 to £400 for this type of application) and have an inspector or third-party tester check the finished installation. In practice the second route costs more than hiring a registered electrician in the first place.
Doing the work without either route is a breach of the Building Regulations. It can leave you without a completion certificate, which solicitors now routinely ask for when a house in Wallington is sold, and it can void the building insurance if a fault later causes a fire.
A consumer unit is not simply a box with switches. The board has to be matched to the incoming supply, the earthing arrangement (TN-C-S, TN-S or TT, which is common in older parts of Beddington and Carshalton with overhead supplies), and the condition of the existing circuits. Before the new board goes in, a competent electrician tests every circuit for insulation resistance, earth continuity and polarity. On a 1930s semi in Wallington it is common to find at least one circuit that would trip a modern RCD straight away because of deteriorated cable or a borrowed neutral.
Since the 18th Edition of BS 7671 and Amendment 2 in 2022, new boards in domestic properties are metal-clad, fitted with surge protection unless a documented risk assessment says otherwise, and increasingly use RCBOs on every circuit rather than two shared RCDs. Getting these choices right is part of the job. So is the main earthing conductor and bonding to gas and water pipes, which is often undersized or missing entirely on older installations and must be brought up to 10mm² before the new board is signed off.
For a typical three-bedroom house in the SM6 area, a straightforward consumer unit replacement with a 10 to 12 way metal board, RCBOs and surge protection usually falls between £550 and £950 including labour, parts and certification. Flats with fewer circuits sit at the lower end. Larger houses in Wallington and Carshalton Beeches with electric showers, an EV charger and outbuildings can run to £1,100 or more.
The final price depends on what the pre-work tests find. If a circuit fails and needs rewiring or fault-finding, or if the main earth needs upgrading, that is extra and should be quoted separately before the work continues. A reputable electrician will tell you this at the survey stage rather than on the day. The job itself normally takes four to six hours, with the power off for most of that time.
Anyone can put a logo on a van. Ask for the registration number and check it on the scheme's own website (the NICEIC and NAPIT registers are both free to search online). The person on the register should be the business you are paying, not a subcontractor who is not covered. After the job you should receive an Electrical Installation Certificate with the test results filled in, and within a few weeks a Building Regulations compliance certificate from the scheme. Keep both with the house documents.
Not lawfully in England without notifying Building Control first and having the work inspected and tested. Without that you will have no certificate, and the work would be a breach of Part P.
Not necessarily, but an old rewirable fuse box or a plastic board with no RCD protection offers far less protection against shock and fire. An Electrical Installation Condition Report (usually £150 to £250 locally) will tell you whether it needs replacing or can stay for now.
Yes, typically for four to six hours. If your meter has no isolator switch, the electrician may need to arrange one with UK Power Networks or your supplier beforehand, so mention this when booking.