Should I Repair or Replace My Consumer Unit (Fuse Box)?

Average UK labour and parts costs — always get multiple quotes from local engineers.

Consumer units last 20–30 years before components become unreliable or fail to meet current safety standards. Older fuse boxes with rewirable fuses (pre-1990s) have no safety benefits over modern RCD-protected units and should be upgraded. Modern units with RCBO protection for each circuit are the current standard.

A full consumer unit replacement (£400–£800) is almost always worth doing if yours is over 20 years old, uses old rewirable fuses, or lacks RCD protection. This isn't just a repair decision — it's a safety upgrade. Individual MCB/RCD replacements are straightforward for smaller faults. A full rewire is only needed if the wiring itself is faulty or the property is very old.

There are three main types of consumer unit found in UK homes. A main switch unit is the simplest, with a single on/off switch and individual MCBs for each circuit — these offer no RCD protection and are now considered outdated. A split-load (dual RCD) unit divides your circuits across two RCD-protected banks, which is the most common setup installed from the mid-2000s onwards. The newest standard is a full RCBO board, which gives every circuit its own individual protection — so a fault on one circuit won't trip anything else. RCBO boards cost slightly more (typically £100–£200 extra) but offer the best protection and are increasingly specified by electricians under the 18th Edition of the IET Wiring Regulations.

• Rewirable fuses — if your unit still has wire-type fuse carriers instead of MCB switches, it predates modern safety standards and should be upgraded.
• Frequent tripping — repeated tripping of the RCD or MCBs without an obvious cause can indicate internal component degradation or wiring faults.
• Burn marks or a smell of burning — any scorch marks, discolouration, or smell near your fuse box requires immediate investigation by a qualified electrician.
• No RCD protection — if your board has no RCD at all, it cannot automatically cut power in the event of an earth fault, which is a serious safety risk.
• Failed EICR — if an Electrical Installation Condition Report flags your consumer unit as unsatisfactory (C1 or C2 codes), replacement is strongly recommended or required.

Consumer unit replacement is classified as notifiable work under Part P of the Building Regulations in England and Wales, meaning it must be done by a registered electrician (e.g., NICEIC or NAPIT registered) who can self-certify the work. An Electrical Installation Condition Report (EICR) costs £150–£300 and is now legally required for rental properties every five years. Upgrading your consumer unit can positively affect your home's EPC rating and is often flagged during property surveys. If you're a landlord, ensuring compliance with the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020 is a legal obligation — and a modern consumer unit is central to that.

Your consumer unit (fuse box) is the nerve centre of your home’s electrical system. While there are a few minor checks you can safely perform, almost all consumer unit work in England and Wales falls under Part P of the Building Regulations and must be carried out by a qualified electrician.

Safe DIY Repairs

• Resetting a tripped RCD or MCB switch — save £60–£100. If a circuit trips, switch off appliances on that circuit, then reset. If it trips again, call an electrician.
• Identifying which circuit has tripped and unplugging the faulty appliance — save £60–£90. Systematically unplug devices on the affected circuit to isolate the fault before calling for help.

Always Hire a Professional

• Full consumer unit replacement (£350–£600) — Notifiable work under Part P Building Regulations. Must be done by an NICEIC, NAPIT, or ELECSA registered electrician who can self-certify.
• Adding new circuits or upgrading to a dual RCD / RCBO board (£200–£450) — Requires Part P compliance, testing, and certification. DIY electrical work of this nature is illegal without building control sign-off.
• Investigating recurring nuisance tripping (£100–£250) — Could indicate a serious wiring fault such as degraded insulation or a damaged cable — professional fault-finding with insulation resistance testing is essential.

Always ensure your electrician provides an Electrical Installation Certificate (EIC) or Minor Works Certificate and notifies Building Control where required.