Your consumer unit — often still called a "fuse box" — is the nerve centre of your home's entire electrical system. Every circuit in your property runs through it, and it's the first line of defence against overloads, short circuits and electric shock. Yet it's one of the most overlooked parts of a home, often out of sight in a hallway cupboard and never given a second thought until something goes wrong.

If your consumer unit is more than 15 years old, or still uses old rewireable fuses rather than modern circuit breakers, it's very likely overdue 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 distribution point for the electrical circuits in your home. It receives the supply from the electricity meter and splits it into individual circuits for lighting, sockets, the cooker, shower, immersion heater and so on. Each circuit is protected by either a circuit breaker (MCB) or a fuse.

Modern consumer units also contain Residual Current Devices (RCDs) — a critical safety feature that detects dangerous earth faults and cuts the power in milliseconds, potentially saving your life in the event of an electric shock or earth fault.

7 Signs You Need a New Consumer Unit

Your Consumer Unit Uses Old Rewireable Fuses

If your "fuse box" contains ceramic or porcelain rewireable fuses (the type where you have to wind new fuse wire when they blow) rather than modern plug-in circuit breakers, it's decades out of date. These offer far less protection than modern MCBs and provide none of the earth fault protection of an RCD.

Circuits Trip Frequently

Occasional tripping can be normal — it's the system doing its job. But if circuits trip regularly without apparent cause, this could indicate the board is overloaded, there's a wiring fault, or the old MCBs are becoming unreliable. A new consumer unit with correctly rated breakers will resolve this.

No RCD Protection

Any consumer unit without RCD protection is a serious safety risk. UK wiring regulations (BS 7671) now require RCD protection on almost all circuits. Without it, a fault to earth — for example, drilling through a cable or an appliance fault — can be fatal.

Signs of Burning, Scorch Marks or a Burning Smell

Scorch marks, melted plastic, or a persistent burning smell near the consumer unit are immediate warning signs of a fault. Turn off the mains and call an electrician straight away — this is a potential fire hazard.

Your Board Can't Accommodate Extra Circuits

Adding a new EV charger, a garden room, a hot tub or solar panels all require new circuits. If your existing consumer unit is full or too old to accept additional circuits, an upgrade or second board may be needed.

Your Home Insurance Requires It

Some home insurers now require proof of a modern consumer unit with RCD protection as a condition of cover, particularly for older properties. If you're having difficulty getting or renewing home insurance, your consumer unit may be the issue.

An EICR Has Highlighted It as a Defect

If you've had an Electrical Installation Condition Report (EICR) carried out and it has identified the consumer unit as a defect — either a C2 (potentially dangerous) or C1 (danger present) — it needs urgent attention.

What Does a Consumer Unit Upgrade Involve?

A consumer unit replacement typically takes 4–8 hours for a standard domestic property, and involves:

Isolating the supply at the meter tails (requires prior notification to the network operator)
Removing the old board and disconnecting all circuits
Installing the new consumer unit in the same or an improved location
Reconnecting all circuits to the new board, including proper RCD protection
Testing and certifying all circuits to BS 7671
Issuing a Minor Electrical Installation Works Certificate or a full Electrical Installation Certificate

As NAPIT registered electricians, Green Earth Sussex can self-certify all consumer unit replacement work — meaning you get your official completion certificate immediately, without waiting for a council building inspector.

How Much Does a Consumer Unit Upgrade Cost?

Consumer unit replacement costs in Sussex typically range from £400 to £900, depending on the size of your property, the number of circuits, the type of board selected, and any remedial work required. We always provide a written fixed-price quote before starting, so there are no surprises.

Not sure if your consumer unit needs replacing?

We recommend starting with an Electrical Installation Condition Report (EICR). This gives you a full picture of the condition of your wiring, consumer unit and all circuits, so you know exactly what needs attention.

Consumer Unit Upgrades Across Sussex

Green Earth Sussex carry out consumer unit upgrades across all of East and West Sussex. Whether you're in Brighton, Hove, Worthing, Crawley, Horsham or anywhere else in the county, our NAPIT approved electricians can assess and upgrade your board quickly and at a competitive price.

Visit our Consumer Unit Upgrades page to find out more or get a quote, or call us directly on 01273 076860.

And if you're unsure whether your property's electrical installation is safe and compliant, book an EICR inspection first — it's the quickest way to get a clear picture of what your home actually needs.

Do I Need a New Consumer Unit? Signs It's Time to Upgrade Your Fuse Box