Single phase vs three phase supply
Most UK homes run on a single-phase electricity supply, which is enough for typical household use. Larger properties, workshops, or homes adding multiple EV chargers or heavy machinery sometimes need a three-phase supply instead — this is arranged with the network operator, not just your electrician, and can take weeks.
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.
New build and extension electrical work
Wiring an extension or new build from scratch is different from rewiring an existing room — it's planned around final wall positions and fittings before plastering, so timing with your builder matters. First-fix electrical work (cabling inside walls) has to happen before plastering; second-fix (sockets, switches, fittings) after.
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.
LED lighting and energy-saving rewires
Swapping halogen downlights for LEDs is usually straightforward, but older dimmer switches often aren't compatible with LED drivers and need replacing alongside the bulbs, or you'll get flickering or a limited dimming range. If you're rewiring a room anyway, it's worth speccing LED-compatible circuits from the start rather than fixing dimmer compatibility later.
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.
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.