Fuse box vs consumer unit — and signs you may need an upgrade
They're the same thing — 'fuse box' is the old term and 'consumer unit' is the modern one. What really matters is age and type: if yours still uses rewireable fuses, has only one or two RCDs covering everything, or sits in a wooden or old painted-metal enclosure, it's likely behind current standards and a good candidate for an upgrade.
Same job, different eras
A fuse box and a consumer unit do the same job: they take the incoming electricity supply and split it into the circuits around your home, with a protective device on each one. 'Fuse box' usually refers to older boards with rewireable fuses; 'consumer unit' is the modern equivalent fitted with circuit breakers (MCBs), RCDs and RCBOs.
Signs yours may be due an upgrade
A few things suggest a board is dated: rewireable fuses (the type with fuse wire) rather than switches; a single RCD covering the whole house; a wooden backboard or an old painted-metal enclosure; no RCD protection at all; or nuisance tripping that takes out half the house at once.
It's also commonly upgraded when you add a big new load — an EV charger, electric shower, solar and battery, or a home extension — because the new circuit and modern protection are far easier to add to an up-to-date board.
What a modern board adds
A current consumer unit typically uses RCBOs, which combine overload and earth-fault protection on each individual circuit. That means a fault on one circuit only trips that circuit — a tripped freezer doesn't plunge the whole house into darkness. Modern boards also usually include surge protection (an SPD), which the latest regulations expect in most homes.
Do you have to upgrade?
Simply having an older board isn't illegal. But an EICR may flag it, and certain new work effectively needs a compliant board to sign off. For most homes it's about protection and peace of mind rather than a legal must — and an EICR is the best way to know exactly where yours stands.
Is a fuse box dangerous?
Not automatically — plenty work fine. But older designs offer less protection against electric shock and fire than a modern RCBO board. An EICR will tell you whether yours is a concern.
Do I legally have to replace an old fuse box?
Not just for being old. It may be recommended on an EICR, and a modern board is often needed to add something like an EV charger safely and compliantly.
What's an RCBO?
An RCBO combines an MCB (overload protection) and an RCD (earth-fault protection) in a single device, per circuit — the modern standard for a consumer unit.