Consumer Unit Replacement or Full Rewire – How to Tell the Difference

If you have been told your electrics need attention — whether following an EICR inspection, an electrician’s assessment, or because something has clearly gone wrong — you may find yourself facing a choice between two very different jobs: a consumer unit replacement or a full house rewire. The difference in cost, disruption and timescale between the two is significant, so understanding which one you actually need matters.

This guide explains the difference clearly, covers the situations where each is appropriate, and helps you understand what questions to ask before agreeing to any work.

What Is the Difference Between the Two Jobs?

A consumer unit replacement involves removing your existing fuse board and installing a modern consumer unit in its place. The wiring throughout your home stays exactly as it is — only the board itself changes. This is appropriate when the wiring in the property is in reasonable condition but the board is outdated, lacks RCD protection, or has failed. It is a relatively contained job that typically takes between four and eight hours and causes one day’s disruption.

A full house rewire involves replacing all of the wiring throughout the property — every cable, every circuit — as well as installing a new consumer unit. It is a significantly more invasive job that involves chasing cables into walls, lifting floorboards, and in most properties requires several days of work and some level of decoration afterwards. It is the appropriate solution when the wiring itself — not just the board — is the problem.

The key question is not which job costs less. It is which job actually fixes the problem. A consumer unit replacement when the wiring is unsafe does not make the property safe. A full rewire when only the board needs replacing is unnecessary expenditure and disruption. Getting the diagnosis right matters.

When Is a Consumer Unit Replacement the Right Answer?

A consumer unit replacement is appropriate when the existing wiring throughout the property is in reasonable condition and the issue is specifically with the board. The most common scenarios where a board replacement is the correct solution are as follows.

The board has no RCD protection

Under current regulations, virtually all circuits in a domestic property require RCD protection. Many consumer units installed before 2000 have no RCD protection at all. Where this is the only significant finding on an EICR , a consumer unit replacement is usually the appropriate remedy. The wiring does not need to be touched — the board is upgraded and RCD protection is provided for all existing circuits.

The board uses rewirable fuses

A rewirable fuse board lacks modern protection and is increasingly a C2 finding on EICR inspections. Replacing the board with a modern unit addresses this finding without requiring any work on the wiring itself — provided the wiring is sound.

The board has physically failed or is damaged

A consumer unit that is warm to the touch, has scorch marks, or has a burning smell around it may have failed internally. Where the failure is confined to the board and the wiring circuits it serves are confirmed as satisfactory, a board replacement resolves the issue.

You are adding significant new demand

If you are installing an EV charger , solar panels , or additional circuits and your existing board lacks capacity, a consumer unit upgrade may be required as part of that work. For a full breakdown of costs see our guide to consumer unit replacement in Cheshire .

When Is a Full House Rewire the Right Answer?

A full rewire is required when the problem is not just with the board but with the wiring throughout the property. The following situations typically warrant a full rewire.

The property has rubber-insulated or fabric-covered cables

Rubber insulation deteriorates with age, becoming brittle and cracking. Fabric-covered cables — common in properties wired before the 1960s — have similarly degraded insulation. Neither can be made safe simply by replacing the consumer unit. The cables need to come out and be replaced throughout. According to Electrical Safety First , deteriorated cable insulation is one of the leading contributory factors in residential electrical fires in the UK.

The property has aluminium wiring

Some properties built in the 1960s and 70s were wired with aluminium conductors rather than copper. Aluminium wiring expands and contracts with temperature changes, loosening connections over time. Where aluminium wiring is present throughout a property, a full rewire is almost always the recommended course of action.

The EICR identifies multiple circuit failures

Where an EICR comes back with C1 or C2 findings across multiple circuits — not just on the consumer unit — it often indicates that the wiring throughout the property is in poor condition. At a certain point, rewiring individual circuits piecemeal becomes both more expensive and more disruptive than a single full rewire. Your electrician should advise clearly on where that crossover point lies.

The property has not been rewired in 40 or more years

Properties that have not been rewired since before the 1980s — common across Cheshire’s stock of Victorian, Edwardian and post-war housing in Crewe, Macclesfield, Winsford and beyond — frequently require a full rewire regardless of whether the consumer unit has been updated. The board may have been changed at some point while the original wiring remains untouched.

For a full guide to rewire costs and timescales, see our house rewire cost guide for Cheshire .

How Do You Know Which One You Need?

The honest answer is: you need a qualified electrician to assess the property. An EICR is the most reliable way to establish the condition of the entire installation — both the board and the wiring — before any decisions are made. Without that assessment, any recommendation is guesswork.

There are some surface indicators that can give you a steer. Round-pin sockets, rewirable fuses, or any visible fabric-covered or rubber-insulated wiring all suggest a full rewire is likely required. A relatively modern installation where the main concern is the absence of RCD protection is more likely to need only a consumer unit replacement. But these are indicators, not diagnoses.

What Questions Should You Ask Your Electrician?

• Have you tested the wiring throughout the property? A consumer unit replacement recommendation without circuit testing is not properly founded.
• What specifically have you found that leads to this recommendation? A qualified electrician should be able to explain the findings clearly.
• Is this a fixed-price quote? Both jobs should be quoted at a fixed price after a survey. Decline open-ended day-rate quotes.
• Are you NAPIT or NICEIC registered? Both jobs are notifiable under Part P of the Building Regulations. You must receive a completion certificate. If your electrician cannot provide this, do not proceed.

We Cover the Whole of Cheshire

Portcullis Power Solutions carries out consumer unit replacements, full house rewires and EICRs across Cheshire from our base in Nantwich. We cover Crewe , Sandbach , Macclesfield , Chester , Northwich , Knutsford and all areas across the county. NAPIT-accredited, fixed quotes, no subcontractors.