Signs you need consumer unit upgrades — and what to do next

Signs you need consumer unit upgrades — and what to do next

A consumer unit (fuse box) is the heart of your home's electrical safety. In Derby properties — especially older terraces and 1950s semis around Oakwood — an ageing consumer unit can hide hazards. Here are clear, practical signs that you should consider a consumer unit upgrade and exactly what to do next.

Common warning signs

• Frequent or unexplained trips: If circuits trip regularly for things they used to run fine on, or multiple appliances trip the entire board, the unit may be overloaded or its protection devices are failing.
• RCDs that don’t reset or test properly: RCDs (residual current devices) are essential for preventing shocks. If the unit won't reset after a trip or the test button doesn’t behave as expected, it’s a serious safety concern.
• Old fuse wire or rewireable fuses: If your consumer unit still uses screw-in fuses or rewireable fuses, it’s outdated. Modern MCBs/RCBOs give better protection and fault isolation.
• Burn marks, scorch smells or buzzing: Any signs of heat, melting, burning or a persistent buzzing noise mean switch off non-essential circuits and call a qualified electrician immediately.
• No RCD protection on ring mains or sockets: Many older boards lack RCD protection on key circuits such as kitchen and garden sockets — these should be assessed and upgraded where required.
• Not enough spare ways: If you’ve added new circuits and the consumer unit is full, adding spurs or jury‑rigging can overload the board. A modern board with spare ways or RCBOs is the correct fix.
• Aluminium wiring or poor earthing/bonding: Older wiring systems and inadequate earthing increase risk. An electrician will test continuity and bonding to decide if an upgrade is needed.
• Property changes or building work: If you’ve had a kitchen refit, loft conversion or added an EV charger, the existing consumer unit may not meet current demands.

Safety first — what to do immediately

1. If you smell burning or see damage, switch off the mains and keep people and pets away from the area. Call a qualified electrician straight away.
2. Don’t attempt DIY repairs on a consumer unit. Working on a live board without correct training and PPE is dangerous and illegal under Part P unless you are suitably certified.
3. Record what’s happening — note which circuits trip and any appliances involved. This helps the electrician diagnose the fault faster.

What an electrician will do during an inspection

• Carry out a visual inspection of the consumer unit, earthing and bonding.
• Test RCDs, MCBs and circuit continuity with portable test gear to identify faults and capacity issues.
• Assess load requirements and future demands (EV charging, new kitchen, smart home devices).
• Recommend either a partial upgrade (e.g. replacing outdated protection devices) or a full consumer unit replacement to current BS 7671 standards.
• Explain notification requirements. As a NAPIT and Part P registered business, CMA Electrics handles required notifications to Local Authority Building Control where applicable and issues the appropriate certificates.

Typical upgrade options (what to expect)

• Fitting a modern consumer unit with individual MCBs and RCD/RCBO protection for better fault isolation.
• Adding dedicated circuits for high‑load appliances (electric ovens, EV chargers) to stop nuisance trips.
• Upgrading earthing and bonding where tests show it’s needed.
• Labelling all circuits clearly and providing test certificates after work is completed.

Factors that affect the scope of work

• Age and condition of wiring in the property
• How many new circuits are needed (EV charger, new kitchen circuits)
• Access to the existing board and whether plaster or cupboards need temporary removal
• Requirement for additional earthing or remedial wiring work

Because each home is different, it’s important to get a site assessment rather than rely on guesswork.

Why choose a registered electrician in Derby

CMA Electrics Ltd is NAPIT and Part P registered with 10 years’ experience working across domestic and new‑build projects in Derby and surrounding areas. We focus on tidy workmanship, clear communication and same‑day or emergency responses when a consumer unit fault creates a safety risk.

Next steps — a short checklist

• If there’s immediate danger (burning smell, sparks), switch off the mains and call an electrician now.
• Book a consumer unit inspection so protective devices can be tested and a load assessment completed.
• Ask for a written recommendation that explains whether a partial repair or full replacement is the safest, most cost‑effective route.
• Confirm certification and notification — ensure any work is issued with an Electrical Installation Certificate and notified where required.

If you’re in Derby and worried about an ageing consumer unit, get in touch. Call +44 7952 962048 or email charles.archer@cmaelectrics.co.uk to arrange an inspection. CMA Electrics Ltd — NAPIT & Part P registered, 10 years’ experience, tidy installations and same‑day response for urgent faults.