Consumer Unit Upgrade Cost London 2025 — Fuse Box Replacement Prices
How much does a consumer unit (fuse board) upgrade cost in London? This guide covers prices for standard replacements, what the 18th Edition regulations require, and what is included.
Consumer Unit Upgrade Costs in London 2025
Consumer unit (fuse board) replacement costs in London in 2025:
- Standard 8-way consumer unit (flat/small property): £400–600
- Standard 12-way consumer unit (2-3 bed house): £500–700
- 16-way consumer unit (larger property): £600–900
- Dual RCD board (18th Edition compliant): £500–750
- Full RCBO board (individual protection per circuit): £700–1,200
- Addition of AFDD (arc fault detection): £100–200 extra per device
These prices include supply of the new consumer unit, installation and all required testing. Part P Building Regulations notification is included — you receive a completion certificate from your NICEIC or NAPIT registered electrician.
When Is a Consumer Unit Upgrade Required?
A consumer unit replacement is typically required in the following circumstances:
- EICR unsatisfactory result: An older consumer unit without RCD protection commonly generates C2 codes on an EICR inspection, requiring upgrade within 28 days.
- Old rewireable fuse (porcelain fuse carrier) board: Pre-1980s boards with rewireable fuses and no RCD protection are no longer compliant and should be replaced.
- Melted or damaged board: Physical damage, scorch marks or heat-damaged plastic require immediate replacement.
- New circuit additions: Adding circuits for an EV charger, home office or kitchen extension is often the trigger to upgrade the consumer unit at the same time.
- Landlord compliance: The EICR requirement under the 2020 Electrical Safety Regulations means many older rental properties are now receiving C2 codes for outdated consumer units.
18th Edition Requirements
The 18th Edition of the IET Wiring Regulations (BS 7671:2018+A2:2022) introduced requirements for Arc Fault Detection Devices (AFDDs) in certain high-risk locations including HMOs, purpose-built flats and bedrooms in houses. AFDDs detect arc faults — irregular electrical discharges that can cause fires — that RCDs cannot detect.
While not retrospectively required for all existing installations, new consumer unit installations in qualifying premises now require AFDD provision. This adds £100–200 per device to the cost of a consumer unit replacement in an HMO or block of flats.
Part P Building Regulations
Consumer unit replacement is notifiable work under Part P of the Building Regulations. NICEIC and NAPIT registered electricians can self-certify compliance — no separate application to Building Control is needed. You receive an Electrical Installation Certificate (EIC) on completion. This documentation is required for property sale conveyancing and for insurance purposes.
Frequently asked questions
How much does a consumer unit upgrade cost in London?
Consumer unit replacement in London costs £400-600 for a standard small property and £600-900 for a larger property with a full RCBO board. AFDD-equipped boards for HMOs cost £700-1,200 depending on the number of circuits.
How long does a consumer unit replacement take?
A straightforward consumer unit replacement typically takes 4-6 hours for a standard residential property. The electricity supply is off for most of this time. We aim to complete all work in a single day visit.
Do I need an EICR before a consumer unit upgrade?
Not necessarily — an EICR is not required before a consumer unit upgrade, though it is good practice to have one to understand the overall condition of the wiring. If your consumer unit upgrade is being done in response to an unsatisfactory EICR result, the upgraded board is inspected and tested as part of the remediation sign-off.
What is the difference between an RCD board and an RCBO board?
An RCD (residual current device) board has one or two RCDs protecting groups of circuits — if one circuit faults, all circuits on that RCD lose power. An RCBO board has an individual RCBO (combined RCD and MCB) per circuit, so a fault on one circuit only trips that single circuit. RCBO boards are more convenient and now standard on new installations.