FREE CHAPTER from ‘A Practical Guide to the Law on Using Commercial Property for Electric Car Charging and Solar and Wind Power’ by Alastair Frew


Electric cars (or EVs as I shall call them) have stopped being a technology of the future and are very much the technology of today. The UK is the world’s 4th largest market for EVs by market share, and 7th largest by total numbers. Recently, Jaguar Cars, that bastion of high-powered petrol engine performance, announced that it would only manufacture EVs from 2025. The throaty roar from a straight-six E-Type has been replaced by the whoosh of an iPace.

Climate change, whatever your view on the subject, is now central to HM Government’s energy policy. In 2017, transport was the largest carbon-emitting sector of the UK economy, accounting for 28% of UK greenhouse gas emissions. Improvements in diesel engine technology had led to a steady reduction in this figure, but the penchant amongst consumers for ever larger cars has resulted in the emissions figure rising again.

EVs are seen as the answer. Despite being 4th in the global league table, in 2019 around 58.5% of licensed cars were petrol, 39.1% diesel and 0.8% were either hybrid or fully electric. At the end of Q2 2020, the figure for EVs (if you include hybrids, which the Government doesn’t as they still have an internal combustion engine) had shot up to 10% of newly registered cars, albeit in the face of a sharp decline in overall registrations.

The assumption made by National Grid ESO, the company which operates our national electricity grid, is that the UK stock of EVs will be well in excess of 3m by 2030, with more than 36 million by 2040.

In this book, I am only considering plug-in electric vehicles to be EVs.

If you are looking to charge an electric car, you can do so outside your home. You simply plug it into a standard domestic 3 pin plug, using the charging cable that will be supplied with the car. Like all appliances, electric cars have dedicated charging cables. In this case, the cable is called an EVSE (electric vehicle service equipment) cable, and it should be standard equipment with all electric cars.

Better than this, would be to have a wall mounted home charging point installed at your home. Why? A dedicated home charging point provides a higher amp rating, so will charge the car battery more quickly, and more safely.

The EVSE cable is intended to protect the car battery from over-charging. The ESVE cable is more properly called an ‘in line charger’ or ‘portable charger’, although people have a habit of calling it a ‘granny cable’. The cable will be 5 or 10 meters long, with a domestic 3-pin plug on one end, and a EVSE plug on the other end. You plug one end into your house, and the other end to your car. The power will come through at 13 amps (depending, of course, on your domestic electricity supply) and your car will be slowly recharged. The ESVE will cut the power when the battery is fully charged, although that will take a long time using a 13-amp domestic supply.

The ESVE in line charge cable should be kept in the boot of the car, so that you can trickle charge your car in almost any location. The problem is that they charge the car very slowly. Typically, an in-line ESVE charge cable will supply 10 amps of current (it must be less than 13 amps, or it will trip your fuse box at home). Put another way, 10 amps multiplied by a domestic rated 230 volts, gives a power output of 2.3 kw per hour. A small EV battery holds 30 kw/h of power, so it will take 12 to 13 hours for a full charge. If you top up your battery overnight every evening, this should be enough. Equally, if your EV is actually a plug-in hybrid, then this will be perfectly sufficient. It is however entirely inadequate if you drive a pure EV and need a quick turnaround after a long journey.

For faster charging, you could look to a dedicated charge point fitted at your home or office.

Whereas an ESVE cable plugged into a socket in your house would take 13hrs to charge your EV battery, it would take just 6 hours using a dedicated charge point to charge a 30kw battery.

Home charging points operate at 230 volts, being the voltage that is available in your house. So, it follows that the power increase is down to an increase in the current, from 13 amps to 16 amps. Remembering that Watts = Amps x Volts, if you are able to install a 32-amp charging point, then the charge time drops again, to three or four hours.

All of this refers to domestic 230-volt “single phase” AC electricity. For really fast charging, you need to use DC power.

Years ago, when Mr Nikola Tesla invented AC electricity, he did so in order to make electricity easier to transport. AC current alternates back and forth, so the total power load on the equipment at any given time is effectively zero. For charging electric batteries, this is of limited use. Good old fashioned Direct Current is the best thing for charging a battery. The irony; Mr Tesla invented AC, but you need DC to charge the huge battery within the EV named in his honour – the Tesla car!

DC electricity is difficult to transmit over long distances, and much more dangerous than AC if “mishandled.” For this reason, houses are supplied with AC power. The National Grid transmits electricity using AC, just as Mr Tesla intended. When you plug your mobile phone into the 3-pin plug at home, the charging plug converts the power from AC to DC, so that your phone battery will charge more quickly. More powerful devices, such as tablet computers, will have larger plugs, so that they can provide more current (more amps) to charge the larger battery more quickly.

The problem is that the speed of charging while using an AC power supply is often limited by the ability of the equipment within the EV’s On Board Charger (OBC) to convert AC to DC, and so to charge the battery. Some small cars have very advanced OBC equipment, allowing their small batteries to be fully charged at home in just a few hours. Conversely, some larger vehicles have a much lower conversion rate (and much larger batteries) meaning that the up-market driver might be off the road for a substantially longer period of more than ten hours for a full charge.

Annoyingly, while all EVs use the ESVE standard, there are still different “shapes” of plug socket in the marketplace. Nissan, for instance, uses the older 5 pin “type 1” socket, while Renault (which owns Nissan!) uses the more modern 7-pin “type 2” socket. BMW, Mercedes, VW, Volvo and Tesla also use Type 2 sockets.

Just to complicate matters, both Type 1 and Type 2 plugs are likely to be replaced by the CCS plug (Combined Charging System), which is proving popular with up market European and North American car manufacturers. South Korean manufacturer Kia also now uses the CCS system, although Nissan and Mitsubishi are holding fast to the Japeanese CHAdeMO standard at present. In the medium term, the CCS standard should simplify matters for European EV owners, as the CCS system can use be used by Type 2 connectors, but at the moment it all remains a bit of a nuisance for EV users, as the dedicated charge point attached to the wall of your office, or indeed your friend’s house, may have the wrong type of socket, requiring you to resort to your slow granny cable.

In the unlikely event that your drove your EV to China, you might find that your car charging sockets don’t fit. China – the world’s largest EV market – and Europe/North America have different electrical standards. China uses the GB/T standard, which is not compatible with the CCS.

It’s just like trying to charge your mobile phone, laptop and tablet – they each need a separate cable, you need to buy everything from the same brand and replace them all every couple of years.

All of this is pretty unimpressive – owners of luxury electric cars will want to be able to charge their vehicles much more quickly.

Domestic power supplies are modest. Home electricity consumption is typically not very large so the electricity company only provides a small amount of power. Added to this, most households are busily consuming most of their available electricity all of the time anyway, running lights, computers, fridges, cookers and heating systems. There just isn’t a great deal left for charging an EV. High speed charging at home remains a distant dream.

As well as the AC-DC issue, there is something called three-phase electricity. Our homes typically use a single-phase power supply, which allow for a maximum EV charging rate of 7kW, which is why many car makers limit their OBC inverters to 7kW, regardless of the size of the battery. Industrial buildings need much more power than this, and demand what electricians call three-phase electricity, which passes through three conductors on its way to the building from the National Grid. This allows for much greater levels of power, as is required by industrial users. Larger office buildings will also have three-phase power, which can provide up to 22kW of power. Three-phase electricity in the UK is 400 volts, enabling must faster charging than 230v domestic power. However, charging your EV outside a commercial building in the UK will always be a little slower than many of the advertised timings, which use data from the USA where they have 480-volt electricity.

The answer is the DC Fast Charger. Using electrical current that has already been converted to DC before it reaches the connection to the vehicle, the EV battery is able to accept the electricity much more quickly. Charging times may be 10 or 15 times faster using DC, as the electricity does not need to be converted within the car’s On Board Charger.

Therefore, public charge points, and those found at office buildings, will always be capable of converting the AC current supplied by the National Grid into DC before sending it down the cable to the car. These conversion units (known as “Inverters”) are very expensive, costing thousands of pounds.

Super-fast charging does of course damage the car’s battery. To counter this, many famous brands of EV will advertise a battery capacity which is much larger than is actually available; as the battery degrades, new battery space is opened up, thereby prolonging its total life. The maximum capacity is however always something of an illusion, a piece of marketing hype. The holy grail of EV battery cells is to find a method of charging which does not cause the internal parts of the battery to corrode during charging. Scientists keep declaring to have found a solution, but the marketplace is yet to see a convincing product.