When does a consumer unit need replacing?
Older fuse boxes with rewireable fuses or plastic (rather than metal) casings don't meet current wiring regulations and are a common reason a rewire quote comes in higher than expected. A modern consumer unit uses RCBOs, which cut power to a single faulty circuit rather than the whole property.
Electrical upgrades: EV chargers, solar PV & smart home systems
Beyond repairs, many electricians now fit EV charging points, solar PV inverters and battery storage, and smart home systems — app-controlled lighting, heating and security. These jobs usually need a separate circuit and, for EV chargers, a dedicated consumer unit way — worth checking your existing setup can support the extra load before booking.
What does an RCD do?
A residual current device cuts power within milliseconds if it detects current leaking to earth — the main protection against electric shock from a faulty appliance or damaged cable. Modern consumer units have RCD protection built in across multiple circuits (RCBOs); older ones may only protect part of the property.
Lighting design and circuit planning
Adding recessed downlights, under-cabinet lighting or dimmer circuits usually means new cabling even if you're keeping the existing consumer unit, since older lighting circuits weren't sized for LED transformers or multiple dimmer switches. Plan lighting changes before, not after, a room's redecorated.
Powering a garden office or outbuilding
Running power to a garden office or outbuilding usually means an armoured cable buried below the recommended depth, its own small consumer unit, and RCD protection at the supply end. This is notifiable work and typically needs building control sign-off alongside the electrical certification.
Understanding the labour vs materials split
Materials — consumer units, cabling, sockets, fittings — are usually a smaller share of an electrical quote than labour, particularly for jobs involving lifting floors or chasing walls. If a quote seems unusually cheap, check whether it's using a lower-spec consumer unit or cabling than a competing quote, not just a lower labour rate.
NICEIC & NAPIT registration explained
NICEIC and NAPIT are the two largest government-authorised Competent Person Schemes for electrical work in the UK. Joining requires a recognised qualification (City & Guilds 2382, the 18th Edition Wiring Regulations, plus a Level 3 NVQ and City & Guilds 2391 for inspection and testing), and ongoing assessment. A registered electrician can self-certify notifiable work without a separate council inspection.
DIY electrical work vs when you need a professional
Under Part P of the Building Regulations, certain electrical work in a home is notifiable — it has to be carried out by a registered electrician who can self-certify it, or separately inspected by your council's building control. New circuits, consumer unit replacements, and any new work in a kitchen or bathroom are notifiable. Like-for-like socket or switch swaps usually aren't.