How do I know if my fuse box is old?

If it has pull-out fuses with fuse wire or cartridges inside, it's an old-style board without RCD protection. If it has a row of switches but no 'test' button, it has circuit breakers but probably no RCD protection either.

Is a plastic consumer unit dangerous?

Not automatically. Since 2016 the wiring regulations have required new consumer units in homes to be made of non-combustible material, usually metal, but an existing plastic unit isn't necessarily unsafe. An EICR will tell you whether it needs attention.

What is the difference between an RCD and an RCBO?

An RCD protects a group of circuits against earth leakage, so one fault can switch off several circuits at once. An RCBO combines a circuit breaker and RCD for a single circuit, so a fault only switches off that one circuit.

Do I have to replace my old fuse box?

Homeowners aren't legally required to replace an old fuse box, but boards without RCD protection offer much less protection against electric shock. Landlords in Wales need a satisfactory EICR, which may require an upgrade.

How long does it take to change a consumer unit?

Usually around a day, depending on the number of circuits and whether any faults are found when the existing wiring is tested.

Fuse Box Types Explained – Do I Need a New Consumer Unit?

Your fuse box — properly called a consumer unit — is where your home’s electrics are controlled and protected. It’s usually under the stairs, in a hallway cupboard or near the front door. What type you have says a lot about how old your electrics are and how well protected you are.

The main types

1. Rewireable fuse boards

Porcelain or plastic fuse carriers that pull out, with a length of fuse wire inside. Common in homes wired before the 1970s–80s.

No RCD protection, so they won’t cut the power fast enough to protect someone touching a live part
Fuse wire can be replaced with the wrong rating
A strong sign the rest of the wiring may be old too — try our rewire check

2. Cartridge fuse boards

Similar to the above but with sealed cartridge fuses. Still usually no RCD protection.

3. Circuit breaker (MCB) boards without an RCD

A row of switches (MCBs) that trip when a circuit is overloaded. Easier to reset than fuses — but if there’s no “test” button, there’s probably no RCD, so no protection against electric shock.

4. Split-load consumer units (one or two RCDs)

Very common from the 2000s onwards. One or two RCDs, each protecting a group of circuits. Much safer — but one fault can switch off half the house, including the fridge-freezer or lights.

5. RCBO consumer units

Each circuit has its own RCBO (a circuit breaker and RCD in one). A fault only switches off the circuit it’s on. This is what we usually recommend for a new installation.

Metal, not plastic

Since 1 January 2016 the wiring regulations have required new consumer units in homes to be housed in non-combustible enclosures — in practice, metal. An existing plastic unit isn’t automatically dangerous, but any replacement will be metal.

Signs it’s time to upgrade

You have rewireable or cartridge fuses
There’s no RCD (“test” button) protection
An EICR has recommended it
You’re adding circuits — an extension, a kitchen, a garden office or outdoor lighting
You’re planning a rewire or renovation anyway

What an upgrade involves

We test the existing circuits first. RCD protection will trip if there are hidden faults, so any problems are found and explained before the new board goes in.
The new consumer unit is fitted, usually in about a day.
Everything is tested again, you get an Electrical Installation Certificate, and notifiable work is signed off with Building Control.

See consumer unit upgrades in Cardiff or get a quote.

Fuse box types explained – do you need a new consumer unit?