The short answer
In England and Wales, replacing a consumer unit is notifiable work under Part P of the Building Regulations. This means the work must either be carried out by a registered (competent-person) electrician who self-certifies it, or the homeowner must notify building control before work starts and have it inspected and approved after. In practice, an unregistered person — including the homeowner — carrying out this work and notifying building control is technically permitted but uncommon; the notification route requires an inspection, comes with a fee, and only passes if the work meets BS 7671. Doing it without any notification or certification at all is a breach of the Building Regulations. The strong practical advice from every professional body is to use a registered electrician.
The question gets asked regularly, and the honest answer is nuanced: the regulations have a building-control route that is technically available to an unregistered person, but the safety risks, legal implications and property-sale consequences mean it is not a sensible approach for a consumer unit replacement.
Part P in brief
- Is it notifiable?Yes — consumer unit replacement is notifiable in England and Wales
- Registered electrician routeSelf-certifies; you receive EIC + Building Regs certificate
- Building control routeMust notify before work; inspection required; fee payable
- Uncertified workBreach of Building Regulations; problem on resale
- Scottish rulesDifferent; confirm with Building Standards Scotland
What Part P of the Building Regulations says
Part P of the Building Regulations applies in England and Wales and sets out which electrical work in dwellings is 'notifiable'. The replacement of a consumer unit is explicitly within scope: it is notifiable work. Notifiable work must be dealt with by one of two routes:
- Route 1 — Registered competent-person electrician: an electrician registered under a government-authorised scheme (NICEIC, NAPIT, ELECSA, STROMA, BRE Group or similar) carries out the work, certifies it themselves under their scheme's authorisation, and issues an Electrical Installation Certificate. The scheme notifies the local authority's building control department. No prior notification by the homeowner is required.
- Route 2 — Building control notification: the person doing the work (which could be the homeowner) notifies the local authority building control department before work starts. Building control (or an approved inspector) then inspects and approves the work on completion, and issues a completion certificate. A fee is charged for this service.
There is no third route. Work done without using either of these routes is in breach of Part P and the Building Regulations.
Why it is not a practical DIY job even on the building-control route
The building-control notification route technically allows an unregistered person to carry out notifiable work if they notify correctly and the work passes inspection. In practice, however, a consumer unit replacement presents serious practical barriers for an unqualified person:
- Live incoming tails: the cables from the electricity meter to the consumer unit remain live at mains voltage even when the main switch is turned off. Only the distribution network operator can make them dead. Working safely in their proximity requires specific electrical knowledge and precautions.
- BS 7671 compliance: the installation must comply with the 18th Edition wiring regulations in full. This includes correct device selection and ratings, conductor sizing, earthing arrangements, SPD requirements, and connection torque settings. An inspector checks compliance with these standards. Incorrect work will fail.
- Testing equipment: before the EIC can be issued (or the building-control inspection signed off), the circuits must be tested with calibrated equipment — insulation resistance testers, loop impedance testers, RCD testers. Most householders do not own this equipment.
- Insurance: most household buildings insurance policies expect electrical work in the home to be carried out by a qualified person. Uncertified electrical work can affect a policy's validity.
The Electrical Safety First guidance and every professional body in the electrical industry advise that a consumer unit replacement should be carried out by a registered electrician. This is not simply a commercial position — it reflects the genuine risks involved.
| Route | Who carries out work | What you receive | Practical for DIY? |
|---|---|---|---|
| Registered electrician (competent person) | Registered electrician | EIC + Building Regs certificate; no prior notice needed | N/A — professional route |
| Building control notification | Anyone — notify first | Completion certificate if work passes inspection | Technically possible but rarely practical |
| No notification, no certification | Anyone | Nothing — breach of Building Regulations | Not legal |
Routes for notifiable work under Part P (England and Wales). Sources: Part P of the Building Regulations; government guidance.
Consequences of uncertified consumer unit work
The consequences of carrying out a consumer unit replacement without proper certification are practical and ongoing, not just theoretical:
- Property sale: when you sell a property, the buyer's solicitor will typically request evidence of building-control compliance for notifiable electrical work. An uncertified consumer unit replacement is one of the most commonly flagged items in conveyancing. You may be required to retrospectively certify the work — which involves a registered electrician inspecting and testing the installation — or provide an indemnity insurance policy, which does not fix the underlying wiring.
- Local authority enforcement: a local authority building control department can require uncertified notifiable work to be inspected, and if it does not comply with the regulations, require it to be put right at the owner's expense.
- Insurance: in the event of a fire or damage event, an insurer investigating the claim may establish that the electrical installation was not certified. This can give grounds for disputing the claim.
- Safety: the certification process exists because the consequences of incorrectly wired consumer units can be fatal. Testing catches faults; certification creates a record that the installation was sound when it was done.
Frequently asked questions
Can a homeowner replace their own consumer unit?
In England and Wales the work is notifiable under Part P. A homeowner could use the building-control notification route — notifying before work starts and having it inspected after — but in practice the technical requirements (BS 7671 compliance, testing equipment, live incoming tails) mean it is not a sensible undertaking for an unqualified person. The normal route is to use a registered (competent-person) electrician.
What happens if I replace a consumer unit without telling anyone?
Doing so is a breach of Part P of the Building Regulations in England and Wales. The local authority can require the work to be inspected and, if non-compliant, put right at your expense. When you sell the property, the absence of a Building Regulations certificate will be flagged in conveyancing.
Does Part P apply if I am replacing like-for-like?
A like-for-like consumer unit replacement is still a notifiable job under Part P. The regulations focus on the type and scope of work, not whether it is a direct replacement or an upgrade.
Sources & further reading
- Electrical Safety First — replacing a consumer unit (best practice guide)
- GOV.UK — Part P: electrical safety in dwellings (Building Regulations)
- NICEIC — what is Part P and who needs to register?
Figures on this page are typical UK ranges drawn from published sources and depend on your specific property and installation. They are guidance, not a quotation.