Home EV charger electrical plan: prepare a clear installation
Most electric cars are charged at home, overnight, on a dedicated circuit that did not exist when the house was built. Before choosing a wallbox, a plan settles the questions that actually drive the cost: where the charge point goes, how the cable gets back to the consumer unit, and whether there is a spare way for it.
Why prepare the plan before choosing the charger?
The power printed on a charger is only one part of the design. The vehicle, parking time, electricity contract, existing distribution board and distance to the parking space all affect the final solution.
An electrical plan brings these decisions together. It shows the actual parking position, the side of the vehicle charging port, the possible cable route and the equipment needed near the distribution board.
- Location of the wallbox or reinforced outlet.
- Distance and route between the distribution board and parking space.
- Indoor, façade, garage or underground conduit route.
- Possible location of load management and sub-metering equipment.
Reinforced outlet or wallbox: what should the plan show?
A reinforced outlet can fit a low daily mileage when the vehicle remains parked for a long time. A wallbox usually offers more power, finer load control and scheduling or monitoring features.
Common comparison points include up to 3.7 kW for slower charging, 7.4 kW on single phase, and 11 or 22 kW when both the vehicle and a three-phase installation support it. The actual rating must be validated against the property and the vehicle.
- Daily driving range to recover.
- Usual parking duration at home.
- Maximum AC power accepted by the vehicle.
- Available property supply and load-management options.
3.7, 7.4, 11 or 22 kW: which power should you install?
Charger power is measured in kilowatts (kW), while kilowatt-hours (kWh) measure battery capacity. The power actually received by the car is always limited by the weakest link: charger, vehicle onboard charger, electricity contract, or property installation.
The most powerful wallbox is therefore not automatically the best choice. When a car remains parked overnight, 3.7 or 7.4 kW may be sufficient; 11 or 22 kW is mainly relevant with a three-phase supply, a compatible vehicle, and a need for faster charging.
- 3.6 kW — single phase, roughly 16 A: slow, but enough for a short commute and a car parked all night.
- 7.4 kW — single phase, roughly 32 A: the standard domestic wallbox in the UK, and what almost every home install ends up being.
- 11 kW — three phase, roughly 16 A per phase: only relevant if the property has a three-phase supply, which few UK homes do.
- 22 kW — three phase, roughly 32 A per phase: requires three phase, a compatible car and the supply capacity to match. Most vehicles cap AC charging at 7.4 or 11 kW anyway.
What should appear on the electrical plan?
The plan should be detailed enough to prepare a quotation without pretending to replace the installer’s technical study. Show the charge point, its dedicated route to the distribution board and the visible constraints along that route.
In Planelico, you can distinguish a wall-mounted charger, pedestal charger, reinforced outlet or future provision. Dedicated symbols also cover dynamic load management, sub-metering, emergency isolation and an outdoor conduit.
After placing a wallbox, select it in the editor to choose 3.7, 7.4, 11, or 22 kW and state whether 6 mA DC detection is integrated. “Generate circuits & panel” then creates the dedicated circuit and corresponding pre-sizing.
- Charger, reinforced outlet or provision for future work.
- Dedicated circuit kept separate from general outlets.
- Dynamic load manager linked to the meter or distribution board.
- Conduit, penetrations and approximate route length.
- Notes about access, outdoor exposure and future extensions.
BS 7671 Section 722 and what it means for the circuit
Section 722 of BS 7671 covers electric vehicle charging installations. The charge point needs its own final circuit back to the consumer unit — it cannot hang off a socket circuit — and that circuit needs both residual-current protection and protection against a broken PEN conductor.
The PEN question is the one that catches people out. Most UK homes are supplied TN-C-S (PME), where an open PEN fault in the network can put a dangerous voltage on the earthed metalwork of anything outdoors. Section 722 requires this to be addressed, either with an earth electrode or with a device that detects the fault and disconnects — a function now built into most domestic chargers.
Installing a new circuit is notifiable work under Part P in England and Wales, so it has to be done by a registered competent person or notified to building control beforehand.
- A dedicated final circuit, typically 32 A for a 7.4 kW charger.
- 30 mA RCD protection, with 6 mA DC fault detection either built into the charger or provided by a Type B device.
- PEN fault protection on a PME supply, or an earth electrode instead.
- Notifiable under Part P: certification by the installer on completion.
Plan smart charging before increasing the supply
Dynamic load management adapts charging to the home’s live demand. It can temporarily reduce the charger when heating, cooking or hot-water loads are high and increase it again when capacity becomes available.
Under the Electric Vehicles (Smart Charge Points) Regulations 2021, charge points sold for private use in Great Britain must have smart functionality by default — scheduling, off-peak response and remote control. Show the intended control link on the plan, not just the power cable: a CT clamp on the incoming supply is a common requirement and needs a route of its own.
Grants: check the current scheme, not an old article
UK support for home charge points has narrowed over the years and is now targeted rather than universal — flat and rental occupants, and households without off-street parking, are the usual focus. Eligibility and amounts change.
Check the current OZEV schemes on GOV.UK at the point you accept a quotation, rather than relying on a figure quoted in an older article or by an installer.
What the plan does not replace
The plan prepares the location, route and desired equipment. On its own it does not calculate voltage drop, final conductor size, protective devices, earthing, diversity or the suitability of the existing distribution board.
Give the PDF to a qualified installer so they can inspect the property, size the circuit and confirm the usable charging power before work starts.
Quick method with Planelico
- 1
Import the property plan
Add the PDF for the home, garage and any relevant outdoor area.
- 2
Place the charge point
Position the wallbox, pedestal, reinforced outlet or future provision beside the parking space.
- 3
Locate the consumer unit
Mark the board that will supply the dedicated circuit, and note whether it has a spare way.
- 4
Draw the proposed route
Show the cable route, penetrations and any outdoor conduit.
- 5
Add smart controls
Mark load management, the CT clamp position on the incoming supply and any sub-metering.
- 6
Export for quotation
Generate a readable PDF for pricing and validation by a registered installer.
Frequently asked questions
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