Planning the electrical wiring in a renovation before you open the walls is the difference between a home that fits the life you'll live in it and a home full of extension leads and "we'll sort it in the next renovation". While the walls are open, moving a circuit costs almost nothing; once they're closed and painted, every change means chasing, dust and repainting.
This guide covers what to decide, who to decide it with, and what you should never leave for later.
1. Use first, cables second
Before talking cable sizes, walk the home room by room and answer:
- Where will the furniture go? A socket behind a chest of drawers is a wasted socket.
- What will be plugged in where? Kitchen and utility rooms concentrate heavy loads (oven, hob, appliances) and need dedicated circuits.
- How is light actually used in that space? Reading, ambience, task and circulation need different controls and points.
- What could change in the next 10 years? An electric car, air conditioning, a home office, another bedroom.
The rule: it's cheaper to install too much now than to open the wall later.
2. The consumer unit is the heart — deal with it first
In a serious renovation, the board almost always needs work:
- Spare capacity — leave 30% of the ways free for future circuits.
- Enough RCDs — the whole house depending on a single RCD that plunges everything into darkness when it trips is not acceptable.
- Separate circuits by function and by zone (lighting, sockets, kitchen, AC, outdoors).
- Surge protection (SPD) — increasingly recommended, especially with electronics and smart-home kit.
- Up-to-date single-line diagram fixed to the board door.
3. Lighting: design the scene, not just the point
The classic mistake is "one light in the middle and we're done". Before ceilings close:
- Define lighting circuits by scene (general, indirect, accent, outdoor).
- Plan control from several points (entrances, bedside, top and bottom of stairs).
- Decide now whether you want dimming — the driver and lamp type depend on it.
- Leave supply provisioned for mirrors, wardrobes, niches and step lighting.
- Outdoors: points for the path, façade and dining area, controlled from inside.
4. Sockets: how many, where and what type
Too few sockets is the number one complaint after a renovation. Points to lock in:
- Kitchen: dedicated circuit(s) for fixed appliances + enough worktop sockets above the counter.
- Living room: a cluster by the TV unit, floor sockets if the sofa sits away from the wall, a point for charging devices.
- Bedrooms: two sockets per bedside table, a point for a desk, a spare socket for a vacuum in the hallway.
- Integrated USB in charging zones (bedside, desk, kitchen).
- Data network: run Ethernet to the TV, office and a central Wi-Fi access point — fibre and mesh will thank you.
5. Prepare for the future while the wall is open
Even if you don't install now, leave the route in place:
- Conduit and box for an EV charger to the garage or parking space.
- Provision for air conditioning / heat pump in the likely rooms, with a condensate drain planned.
- Smart-home pre-wiring — a neutral in every switch box, conduit for electric blinds and curtains.
- Spare conduit between floors and up to the loft/garage.
- Supply for solar panels / battery back to the board, if the roof has potential.
6. Who decides what (and when)
- Before the design: client + electrician + (if any) architect or designer define uses and the socket/lighting layouts.
- Before chasing walls: confirmation on site, with marks on the walls at real height.
- Before closing the chases: photograph everything — you'll be grateful in five years.
- Before painting: testing and certification.
Conclusion
The electrical wiring in a renovation is decided in a two-hour conversation before the work and lived with for 20 years. The costliest mistakes — too few sockets, a single RCD, no provision for an electric car or smart home — aren't technical failures, they're decisions nobody made in time.
Renovating? LumineLab handles the needs survey, the socket and lighting layout and certified installation. Book a site visit before the first wall is opened.