Electrical advice · Hertfordshire
When Should You Replace a Consumer Unit?
Consumer units don't come with an expiry date, and age alone isn't a reason to replace one. But there are clear signs that a board — or the installation behind it — needs looking at.
Old fuse boxes and consumer units
Many older properties still have boards installed decades ago. Some are perfectly serviceable; others lack protection that is now standard. The question isn't how old it is, but whether it protects the people and property it serves.
Fuse wire systems
Rewirable fuses use a length of wire that melts when a circuit is overloaded. They can be rewired with the wrong rating, offer no protection against electric shock from earth leakage, and are slower to disconnect than modern circuit breakers.
Lack of modern protective devices
If your board has no RCD protection — or only some circuits are covered — an upgrade is often recommended, particularly for socket circuits and bathrooms.
Warning signs to act on
Repeated tripping
Occasional tripping is the board doing its job. Frequent tripping with no obvious cause may point to a circuit fault or an unsuitable board. See what to do if your consumer unit keeps tripping.
Damage or overheating
Cracked casings, discoloured plastic, scorch marks or a board that feels warm are all signs of a problem.
Burning smells or unusual noises
A burning smell, buzzing or crackling from the board should be treated as urgent. If it's safe to do so, switch off at the main switch and call an electrician straight away.
Alterations, extensions and changes
Adding an extension, kitchen, loft conversion, EV charger or heat pump often means new circuits. If the existing board has no spare ways, or can't provide suitable protection for the new work, replacement may be the sensible option.
When an inspection identifies issues
An Electrical Installation Condition Report (EICR) may record observations relating to the board. A C1 or C2 code means remedial work is required; a C3 is a recommendation for improvement. Read more in our guide on how often an EICR should be done.
Why you shouldn't replace it yourself
Parts of the consumer unit remain live even with the main switch off, and the work is notifiable under Building Regulations. It must be tested and certified — DIY replacement puts you at risk and leaves you without the paperwork.
What an electrician will check
- The condition and type of the existing board
- Main earthing and protective bonding
- Insulation resistance and condition of each circuit
- Whether the board has capacity for current and future needs
When to contact an electrician
- Immediately, if you notice burning smells, scorching, sparking or crackling
- If a circuit trips repeatedly and won't stay reset
- If you still have rewirable fuses or no RCD protection
- Before planning an extension, rewire or EV charger
- If an EICR has recommended work on the board
Related guides
Not sure about your board?
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