Electrical planning in new builds and renovations

Electrical planning in new builds and renovations, what architects and developers need to know, architectural design advice

Electrical Planning in New Builds and Renovations: Architects and Developers Need to Know

13 May 2026

Nobody talks about the electrical spec until something goes wrong. That’s the problem.

By the time a project is halfway through the first fix, the decisions that actually matter have already been made. Cable routes are set. Consumer unit positions are fixed. Load calculations, if anyone bothered to do them, are baked into a design that nobody’s going to revisit. And yet architects and developers still treat electrical planning like a trade package that can be dropped in at the last minute.

It can’t. And the projects that treat it that way end up paying for it.

Why Electrical Planning Can’t Be Left Until Later

Power demand has changed beyond recognition in the last fifteen years. A house that felt well-specified in 2010 can struggle to cope with modern life today. Home offices, EV chargers, underfloor heating, smart home systems, heat pumps, the load on a typical domestic installation has multiplied, and commercial properties have changed even more dramatically.

When electrical infrastructure isn’t planned for future demand from the start, the building dates faster than it should. Upgrades get needed within a few years of completion. That costs money, disrupts occupants, and reflects badly on everyone who signed off the original design.

There’s a safety dimension too. Electrical faults are behind roughly 14,000 dwelling fires a year in the UK, according to Home Office figures. A properly planned and certified installation reduces that risk significantly. A poorly specified one quietly increases it.

The EICR: Starting Any Renovation the Right Way

On any renovation project touching an existing electrical installation, the first step should always be an Electrical Installation Condition Report.

An EICR gives you the full picture of what you’re inheriting. Wiring condition, circuit capacity, earthing and bonding, consumer unit age and type, it surfaces problems before they become expensive surprises mid-build. Without it, you’re designing an extension or refurbishment on top of an installation you don’t actually understand.

The things an EICR typically flags include:

Old wiring that’s deteriorated to the point of being a fire or shock risk
Circuits that are already running close to their limits
Consumer units that don’t meet current standards
Earthing deficiencies that could put the whole installation at risk

For landlords there’s no choice in the matter. EICR inspections are a legal requirement in England’s private rented sector, due at least every five years. But even where it isn’t mandated, it’s the only sensible starting point. You can’t plan properly without knowing what you’re working with.

EV Charging: Design It In, Don’t Bolt It On

The 2035 deadline for ending new petrol and diesel car sales in the UK isn’t far away. Any building going up today, residential or commercial, is going to need EV charging infrastructure to stay functional and attractive in the years ahead.

The issue is that retrofitting EV charging into a finished building is genuinely painful. Trenches get dug through completed surfaces. Supply cables that weren’t sized for the additional load need replacing. New distribution boards get added. Tenants and residents get disrupted. The cost of all of that adds up fast.

None of it is necessary if EV charging is factored in from the design stage. Getting the cable routes right, sizing the supply correctly, choosing the right hardware, all of that is straightforward when it happens before the floors are laid and the walls are plastered. It’s a significant and avoidable expense when it happens afterwards.

Planning authorities in many parts of the UK are also increasingly requiring EV provision as a condition of consent. Specifying it from the outset removes that hurdle and strengthens the project.

LED Lighting: There’s More to It Than Switching Fittings

Most projects use LED lighting now. That’s not the same as having a well-designed LED lighting scheme.

There’s a real difference between fitting LED downlighters because they’re cheap to run and actually thinking through how a space is going to be lit. A good lighting scheme starts with questions about how the space will be used and what the light needs to do, then works backwards from there.

The things worth thinking through properly include:

Colour rendering index, which affects how materials and finishes actually look under artificial light
Lux levels matched to the function of each area rather than applied uniformly
Dimming and control systems that tie into wider building management
Access for maintenance and realistic lamp replacement schedules

When lighting gets modelled in 3D before anything is ordered, design teams can see exactly what they’re getting and what it will cost to run. For commercial clients especially, the numbers matter. A retail or office space moving away from older fluorescent fittings to a properly designed LED scheme can cut lighting energy use by more than half. Over five years, that’s a meaningful return.

Power Quality and Data Logging: The Questions Nobody Asks

Here’s something that rarely comes up in project meetings: once this building is occupied and running at full load, how will the electrical installation actually perform?

Power quality problems such as harmonic distortion, voltage fluctuations and poor power factor don’t announce themselves. Equipment runs badly, fails earlier than it should, or draws more power than it needs to. Energy bills creep up. Warranties get invalidated. And because none of it is visible, it tends to go undiagnosed for years.

Data logging solves this by recording real performance over time. What the monitoring reveals is often surprising:

Load patterns that nobody anticipated at the design stage
Harmonic distortion affecting sensitive equipment
Power factor problems quietly inflating energy costs
Opportunities to rebalance loads and improve efficiency

For commercial developers, this kind of analysis turns electrical specification from a guessing game into something based on actual evidence. It’s especially useful in mixed-use or industrial settings where the load profile is complex and the cost of getting it wrong is high.

Automated Barriers and Gate Systems: Get the Groundworks Right

Automated barriers and gate systems are becoming standard on commercial and mixed-use developments. They’re also one of the areas where poor electrical preparation causes the most problems.

The civil and electrical groundwork needs to be right before any of the visible installation happens. When it isn’t, the failures are predictable:

Not enough conduit laid during groundworks to carry the cables needed
Power supplies at barrier and gate positions that aren’t adequate for the motor load
No provision for data cabling to serve intercoms and access control
Systems installed with no thought for how they’ll be expanded or replaced later

Gate Safe accreditation is what to look for in a contractor working on powered gate and barrier systems. It’s the relevant safety standard and it matters. A gate that malfunctions and injures someone creates serious liability for the building owner and developer, not just the installer.

These systems also need ongoing maintenance to stay compliant. That’s worth building into the handover documentation from the start, and worth considering when choosing who does the installation.

What to Look for in an Electrical Contractor

The projects that go smoothly are the ones where the electrical contractor is involved early. Not at first fix. Not once the layout is finalised. Early, when there’s still room to influence decisions without ripping things up.

Contractors like Eastern Electrical, based in Norwich and working across Norfolk, Suffolk, and Cambridgeshire, are the kind of outfit worth bringing in at that stage. NAPIT registered, capable of contributing to the design as well as carrying out the installation, and experienced across commercial and residential work.

When evaluating any electrical contractor for a significant project, the things that matter are:

NAPIT or NICEIC registration, which confirms they’re working to BS 7671
Genuine design capability, not just installation
Experience across the project type you’re working on
The ability to handle EICR, testing, and commissioning as well as the build
An understanding of how electrical systems interact with the rest of the building

Registration with a competent person scheme also means the contractor can self-certify their work. That keeps building control sign-off straightforward. Without it, third-party sign-off adds time and cost to every stage.

The Cost of Getting It Wrong

Construction rework is expensive. Industry research puts the cost of defects and rework at somewhere between 5% and 12% of total project costs. Electrical rework sits at the more disruptive end of that range. Chasing out plastered walls, replacing cable runs, retrofitting circuits that should have been there from the start.

The logic is simple. Design time at the specification stage is cheap. Correcting a poorly planned installation after practical completion is not.

For anyone putting together project budgets, a well-specified electrical package covering EV charging, LED lighting design, EICR and power quality monitoring is a core cost. Cutting it to improve the numbers on paper tends to produce worse numbers in reality.

Buildings that are efficient, compliant, and ready for how people actually live and work are more valuable. They let faster, they sell better, and they cost less to run. The electrical specification is a big part of what determines whether a building lands in that category or not.

It is not the most visible part of a project. But it is one of the most consequential.

Comments on this guide to Electrical Planning in New Builds and Renovations: What Architects and Developers Need to Know article are welcome.

Architectural Design

Architectural Designs

Stefan cel Mare Building, Bucharest, Romania
Architects: Lauster & Radu Arhitecti

photograph : Andrei Margulescu
Stefan cel Mare Building in Bucharest