Consumer unit replacement in London

Many London homes are still running on a board installed decades ago: rewireable fuses, a wooden back, no RCD protection, and a set of faded pencil labels that no longer match the circuits behind them. It works, in the sense that the lights come on. What it does not do is disconnect quickly enough when something goes wrong.

A modern consumer unit adds residual current protection, which cuts the supply in a fraction of a second if current starts flowing where it should not — through a nail in a cable, damp in an outdoor socket, or a person.

What a replacement involves

• The existing installation is inspected and the circuits identified
• Circuits are tested before the new board goes in, because a new board will reveal existing faults
• The old board is removed and the new consumer unit installed and connected
• Protective devices are selected for each circuit and its load
• Everything is tested, and every circuit is labelled so it can be understood later
• You are shown how to reset it, and what each switch actually controls

Signs your board may need replacing

• Rewireable fuses with fuse wire, rather than switches you can reset
• A wooden or metal-clad board with no RCD, and no test button
• Circuits that trip regularly, or one main switch that takes the whole house out
• Labels that are missing, wrong, or written in pencil on masking tape
• Scorching, rust or a burning smell at the board
• No spare ways left, because every extension has been squeezed in

An honest word about existing faults

A new consumer unit with RCD protection is more sensitive than what it replaces. If the existing wiring has borderline faults — damp in a garden circuit, deteriorated insulation on an old cable, a neutral and earth touching somewhere — the new board will find them and trip.

This is why the circuits are tested before the board is changed, not after. It means you are told about problems in advance, and can decide what to do, rather than discovering them on the evening the new board goes in.

Why this is not DIY work

Replacing a consumer unit means working at the origin of the installation, where the incoming supply arrives. It requires the supply to be isolated, the circuits to be tested and certified, and the work to be notified. It is not a job to attempt, and it is not a job to leave to someone who will not test what they have connected.

Consumer unit replacement across London

Consumer units are replaced for homeowners across London, on its own or as part of a rewire. If you are not sure whether your board needs replacing, an EICR will tell you where the installation actually stands. A photograph of the board sent with your enquiry is usually enough for an initial view.