Your consumer unit — also known as a fuse board or fuse box — is the nerve centre of your home's electrical system. It controls every circuit in the property and protects you from overloads, short circuits, and electrical fires. Yet many London homes are still running on outdated units that were installed decades ago, long before modern safety standards existed.

If your home has an old rewirable fuse board, a plastic-cased unit without RCDs, or one that trips constantly, it may be time for an upgrade. Here's everything you need to know.

What Is a Consumer Unit and What Does It Do?

A consumer unit is the metal or plastic enclosure that houses your circuit breakers (or fuses), RCDs (Residual Current Devices), and main switch. It distributes electricity from the mains supply to individual circuits throughout your home — lighting, sockets, cooker, shower, and so on.

Modern consumer units are fitted with:

• MCBs (Miniature Circuit Breakers) — trip automatically if a circuit is overloaded
• RCDs (Residual Current Devices) — cut power within milliseconds if they detect a fault to earth, protecting against electric shock
• RCBOs (Combined MCB + RCD) — offer individual circuit protection

Older fuse boards use rewirable fuses or early MCBs without RCD protection, which offer far less safety.

Signs You Need a Consumer Unit Upgrade

Not sure whether your board needs replacing? Here are the most common warning signs:

1. You Have a Wooden or Older Plastic Fuse Board

Wooden fuse boards are a serious fire hazard. They were common in properties built before the 1960s and are no longer compliant with current wiring regulations (BS 7671). If your board is wooden, it needs replacing immediately.

2. No RCD Protection

Since the 17th Edition of the Wiring Regulations (2008), all new consumer units must include RCD protection. If your board doesn't have RCDs, you're missing a critical layer of protection against electric shock — particularly important in kitchens, bathrooms, and outdoors.

3. Fuses That Blow Repeatedly

If you're regularly replacing fuse wire or resetting breakers, it's a sign your circuits are struggling with the electrical demand of a modern home. Older boards were designed for far fewer appliances than we use today.

4. You're Having Electrical Work Done

If you're adding a new circuit — for an EV charger, electric shower, or home extension — your electrician may find that your existing board doesn't have the capacity or the right protection to accommodate it safely.

5. You're Selling or Letting the Property

Landlords are legally required to have a valid EICR (Electrical Installation Condition Report) for all rental properties. An outdated consumer unit is one of the most common reasons an EICR comes back with a C2 (potentially dangerous) or C1 (danger present) code, which must be remedied before the property can be let.

6. Your Home Insurance Is Affected

Some insurers will not cover properties with older fuse boards, or may charge higher premiums. Upgrading to a modern consumer unit can actually reduce your insurance costs.

What Does a Consumer Unit Upgrade Involve?

A consumer unit upgrade is a straightforward job for a qualified electrician, typically completed in a single day. Here's what to expect:

1. Assessment — Your electrician will inspect the existing installation and confirm the scope of work
2. Isolation — The power is turned off at the mains
3. Removal — The old unit is carefully disconnected and removed
4. Installation — A new metal-clad consumer unit is fitted (metal casing is required by BS 7671:2018)
5. Testing — All circuits are tested to confirm they're safe and compliant
6. Certification — You receive an Electrical Installation Certificate (EIC) confirming the work meets current regulations

The whole process usually takes 4–8 hours depending on the number of circuits and the condition of the existing wiring.

How Much Does a Consumer Unit Upgrade Cost in London?

Prices vary depending on the size of the property and the number of circuits, but as a general guide:

• 1–2 bedroom flat: from £450–£600
• 3 bedroom house: from £550–£750
• 4+ bedroom house: from £700–£950

These prices include labour, the new consumer unit, and the Electrical Installation Certificate. Additional work — such as remedial repairs to existing wiring — may be quoted separately.

Always get a written quote from a NICEIC-registered electrician before work begins.

Does It Need to Be a Metal Consumer Unit?

Yes. Since the 18th Edition of the Wiring Regulations (BS 7671:2018), all new consumer units installed in domestic properties must have a metal enclosure. This is to reduce the risk of fire spreading if an arc fault occurs inside the unit.

If an electrician quotes you for a plastic consumer unit, that's a red flag — it wouldn't be compliant with current regulations.

Do I Need Building Regulations Approval?

Yes. A consumer unit replacement is notifiable work under Part P of the Building Regulations. Your electrician must either be registered with a competent person scheme (such as NICEIC) — in which case they can self-certify the work — or submit a building notice to your local authority before starting.

At Olectrics Ltd, all our electricians are NICEIC-registered, so we handle the certification and notification process on your behalf. You'll receive your Electrical Installation Certificate and, where required, a Building Regulations Compliance Certificate.

Can I Upgrade My Consumer Unit Myself?

No. Consumer unit replacement is notifiable electrical work under Part P of the Building Regulations and must be carried out by a qualified, registered electrician. Attempting this work yourself is illegal, dangerous, and will invalidate your home insurance.

How to Book a Consumer Unit Upgrade in London

If you're based in London and think your consumer unit needs replacing, the first step is to get a qualified electrician to assess your installation. In many cases, we can give you a fixed-price quote over the phone based on the size of your property and the number of circuits.

Olectrics Ltd are NICEIC-registered electricians based in Kew, covering all 24 London boroughs. We carry out consumer unit upgrades to the latest BS 7671:2018 standards and provide full certification on completion.

Call us on 07946 436585 or use our online contact form to book a free quote. We typically respond within the hour.