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Homeowner guide · consumer-unit upgrades

Do I need a new consumer unit—or is my existing fusebox still suitable?

An older fusebox is not automatically unsafe and a modern-looking unit is not automatically fault-free. The answer depends on condition, circuit protection, test results, planned work and the installation around it.

Written and reviewed by Shaun JonesElectrician · SL4 Electrical Services · Last reviewed 21 August 2026
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The simple answer

Age and colour alone are not enough to decide.

A proper assessment looks for damage, secure connections, effective earthing, suitable protective devices, clear identification and test results from the connected circuits.

An upgrade may be sensible when protection is limited, the enclosure is damaged, there is evidence of overheating, alterations need additional protection or new work cannot be safely accommodated.

What may be happening

Reasons an upgrade may be recommended.

No or limited RCD protectionOlder boards may leave some or all circuits without modern residual-current protection.
Damage or overheatingScorching, cracking, melting, burning smells or deteriorated components need prompt assessment.
Poor circuit arrangementMissing labels, unsuitable devices, mixed components or little space can make safe alteration difficult.
Planned new workEV charging, new circuits or major alterations may require protection the existing arrangement cannot suitably provide.

What to do safely

Get evidence before agreeing to replacement.

  1. 01
    Photograph the normal frontOpen only the user flap so the breaker labels and test buttons are visible. Never remove a screwed cover.
  2. 02
    Find previous certificatesAn EICR, installation certificate or consumer-unit schedule provides useful history.
  3. 03
    Explain planned workThe best solution depends on whether you are adding circuits, an EV charger, kitchen equipment or other loads.
  4. 04
    Ask for testing and a clear explanationThe electrician should explain why replacement is recommended and what testing or remedial work is included.

A consumer-unit change involves live supply equipment, safe isolation, inspection, testing and certification. It is not a homeowner DIY task.

Authoritative guidanceIET: consumer units and protective devices ↗

Common questions

What homeowners usually ask.

Does a plastic consumer unit have to be replaced?

Not solely because it is plastic. Its condition, location, protective devices, connections and the rest of the installation must be assessed. An electrician may recommend improvement without claiming it is automatically dangerous.

Does a new consumer unit mean I need a rewire?

No. The existing circuits are inspected and tested to confirm whether they are suitable to connect to the new unit. Defects may need correcting, but a consumer-unit replacement does not automatically require a full rewire.

What is the benefit of individual RCBOs?

Each circuit receives its own overcurrent and residual-current protection. A fault on one circuit is therefore less likely to switch off unrelated circuits than on a board using shared RCDs.

Continue learning

What is inside a consumer unit?Read guide →What an RCD doesRead guide →
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