Fuse Board Upgrade: Signs You Need One & What to Expect

Your fuse board — also known as a consumer unit — is the heart of your home's electrical system. It distributes power to every circuit and provides critical safety protection. But if your board is outdated, it may not be keeping you safe. Here's how to tell if you need an upgrade and exactly what the process involves.

What Is a Fuse Board?

A fuse board (consumer unit) is the metal or plastic box, usually near your front door or in a cupboard, where your electricity supply is split into individual circuits — one for your lights, one for your sockets, one for your cooker, and so on.

Modern consumer units contain MCBs (Miniature Circuit Breakers) that trip automatically when they detect a fault, and RCDs (Residual Current Devices) that cut the power in milliseconds if they detect a current leak — such as electricity flowing through a person. Older boards may use rewirable fuses or cartridge fuses that lack this life-saving RCD protection.

Signs Your Fuse Board Needs Replacing

Not sure if your fuse board is due for an upgrade? Here are the most common warning signs:

• Rewirable fuses: If your board has fuse wire that you replace manually, it's decades out of date
• No RCD protection: Modern regulations require RCD protection on all circuits. If your board doesn't have an RCD, it won't protect against electric shock
• Frequent tripping: Circuits tripping regularly can indicate overloaded or damaged circuits
• Scorch marks or burning smell: Any visible damage or heat discolouration on the board is a serious safety concern
• Wooden backing board: Very old installations may have a wooden board, which is a fire risk
• Board is over 25 years old: Even if it looks fine, the internal components may have degraded
• Failed EICR: An EICR inspection may recommend or require a fuse board upgrade as part of remedial work
• Adding new circuits: If you're extending your home or adding high-power appliances, your existing board may not have capacity

What Does a Fuse Board Upgrade Involve?

A fuse board upgrade is a common job for a qualified electrician, and here's what happens step by step:

1. Assessment: We inspect your current board, count the circuits, and assess whether any additional work is needed (such as earthing upgrades)
2. Power off: The mains supply is isolated. The power will be off for the duration of the swap — typically 4–6 hours
3. Old board removed: The existing fuse board is carefully disconnected and removed
4. New consumer unit installed: A modern, metal-clad consumer unit is fitted with dual RCD protection and individual MCBs for each circuit
5. Testing: Every circuit is tested for correct operation, insulation resistance, polarity, and earth fault loop impedance
6. Certification: An Electrical Installation Certificate is issued and the work is registered with your Local Authority Building Control via NAPIT

How Much Does a Fuse Board Upgrade Cost?

In London, a standard fuse board upgrade typically costs between £500 and £800, depending on:

• The number of circuits in your property
• Whether additional earthing or bonding work is needed
• The type of consumer unit (standard vs. surge-protected)
• Ease of access to the existing board

This price should include the new consumer unit, all labour, full testing, and certification. For a broader view of typical electrician prices, see our London electrician cost guide.

Is a Fuse Board Upgrade Worth It?

Absolutely. A modern consumer unit with RCD protection significantly reduces the risk of:

• Electric shock: RCDs detect current leaks and cut the power in under 40 milliseconds
• Electrical fires: MCBs and RCDs prevent overloaded circuits from causing fires
• EICR failure: An up-to-date board helps your property pass its next EICR inspection
• Insurance issues: Some insurers won't cover properties with non-compliant electrical installations

For landlords, having a compliant fuse board is often essential for passing the legally required EICR certificate. It's one of the most cost-effective safety improvements you can make to any property.

Book a Fuse Board Upgrade in London

OS Electrical Safety Ltd carries out fuse board upgrades across all London boroughs. All work is NAPIT certified, fully insured, and covered by our 2-year workmanship guarantee. View our domestic electrical services or get in touch today.