The consumer unit, still commonly called a fuse box, is the heart of your home electrical system. Every circuit passes through it, and every protection device lives inside it. If yours is more than fifteen years old, it almost certainly lacks the safety features required by modern standards. Upgrading to a metal-clad unit with residual current devices is one of the most impactful safety improvements a homeowner can make.
Why Old Consumer Units Are a Risk
Plastic consumer units were banned for new installations in 2016 because they offer no fire containment if a fault develops inside the enclosure. A loose connection overheating or a circuit breaker failing can generate enough heat to ignite the plastic casing, allowing fire to spread into the wall cavity. Metal consumer units are non-combustible and designed to contain any internal fire.
Older units may also lack earth leakage protection. Rewireable fuses and even some older circuit breakers do not detect earth faults, which means a person touching a live metal part could receive a fatal shock before the fuse blows. RCDs and RCBOs detect earth leakage in milliseconds and cut the power before injury occurs.
What a Modern Consumer Unit Includes
- Metal enclosure compliant with BS EN 61439-3 for fire containment
- Main switch for complete isolation of the installation
- Surge protection device to guard against voltage spikes from lightning or grid switching
- RCBOs on every circuit for individual overload and earth fault protection
- A separate RCD for any circuits that cannot use RCBOs due to compatibility
- Neat cable management and adequate spare ways for future expansion
The Upgrade Process
A consumer unit changeover typically takes one day for a standard domestic property. We start by carrying out insulation resistance and continuity tests on all existing circuits to confirm they are safe to reconnect. The old unit is removed, the new one is mounted and connected, and every circuit is tested thoroughly before power is restored.
We also take the opportunity to check your main earthing and bonding. Many older homes in Leicester have undersized earth conductors or no supplementary bonding to gas and water pipes. These are corrected during the upgrade to bring the installation up to current standards.
Expert Tip
All consumer unit upgrades are notifiable under Part P of the Building Regulations. As a NICEIC registered contractor, D3C Electrical self-certifies the work and provides the compliance certificate directly to your local building control department.
