Consumer Unit Upgrade Guide 2025 — Costs, When You Need It & What to Expect

What is a Consumer Unit?

A consumer unit (formerly called a fuse box or distribution board) is the control panel for your home's electrical system. It contains:

• MCBs (Miniature Circuit Breakers): Protect individual circuits from overload
• RCDs (Residual Current Devices): Protect against electric shock
• RCBOs: Combined MCB and RCD for individual circuit protection

Signs You Need to Upgrade

• Old rewirable fuses: Traditional fuse wire is outdated and less safe
• No RCD protection: Modern safety requires RCD protection on all circuits
• Frequently tripping circuits: Often indicates overloaded or faulty circuits
• Adding new circuits: EV chargers, hot tubs, or extensions may require board upgrades
• Insurer requires it: Some insurers demand modern consumer units
• Surveyor flagged it: Property surveys often recommend upgrades

Types of Consumer Unit

• Single RCD: Older style, provides basic protection. All circuits protected by one RCD. Cheapest option but less convenient — one fault can trip everything.
• Dual RCD: Most common modern type. Two RCDs split circuits between them. Better convenience — one fault only trips half the house.
• RCBO: Best protection available. Individual RCD protection per circuit. More expensive but the ultimate in safety and convenience.

Cost Breakdown

• Single RCD consumer unit: £500 – £700
• Dual RCD consumer unit: £600 – £900
• RCBO consumer unit: £800 – £1,200

Costs vary based on number of circuits, existing wiring condition, and location.

What's Involved

1. Isolate supply: Electrician works with your supplier to safely disconnect power
2. Remove old board: Carefully disconnect and remove the existing consumer unit
3. Install new board: Mount and connect the new consumer unit
4. Test all circuits: Full testing of every circuit in the property
5. Issue certificates: Part P notification and Electrical Installation Certificate

Typical duration: 4-8 hours for a standard domestic installation.

Must Be Done by Part P Registered Electrician

Consumer unit replacement is notifiable work under Part P Building Regulations. You must use a Part P registered electrician who will:

• Notify building control of the work
• Provide a Part P certificate
• Issue an Electrical Installation Certificate

After the Upgrade

Benefits of a modern consumer unit include:

• No more replacing fuses — simply reset the MCB
• Better protection against electric shock
• Easier to add new circuits in future
• Meets current building regulations
• Satisfies insurance requirements
• Makes your property more attractive to buyers

Related Pages

• Fuse Board Upgrade
• Electricians in Burnham
• Electricians in Northolt
• Electricians in Ickenham