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.
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.
First fix and second fix, explained
On a rewire or new build, "first fix" is running cables through walls and floors before they're closed up; "second fix" is fitting sockets, switches and light fittings once decorating is done. Getting the timing right with other trades on site avoids cables being covered before they're tested.
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.
Rewiring a listed or period property
Listed building consent can be needed for chasing cable runs into original plaster or masonry, even though the electrical work itself is assessed the same way as any other property under Part P. Conduit and surface-mounted cabling are sometimes used instead of chasing into walls specifically to avoid this — worth discussing with an electrician who's worked on listed properties before.
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.
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.
Garage and workshop power
Running power to a detached garage or workshop means an armoured cable, usually buried, and its own consumer unit or sub-board with RCD protection at the supply end. If you're planning to run power tools or an EV charger from it, size the supply for that from the start — upgrading later usually means digging the cable run up again.