Charging an EV (electric vehicle) safely

92% of all EV owners charge their vehicles via standard mains sockets at home. This is how you can prevent overloads and fires in your electrical system at home.

Check capacity and condition before charging

Most EV owners charge their vehicles via standard mains sockets at home. If you normally use a standard mains socket to charge your EV, you should get an electrician to check the condition of the charging socket, and to check whether your electrical system can handle the draw.

Prevent overheating

DSB recommends that the fuse in the socket you use for charging your EV is no more than 10A. This is to reduce the chance of overheating, as charging an EV loads the circuit to its maximum for several hours. The circuit should not be used for anything other than charging, and it must have an earth leakage circuit breaker. This is a requirement for any new circuits intended for EV charging.

Install a dedicated circuit

Some vehicles have such a big battery capacity that they require a high charging current to charge the battery overnight. You would then need to install a dedicated 32A three-phase circuit that supplies a special charging socket. If you have this type of vehicle, you may need to ask your electricity supplier to raise your subscription capacity and increase the size of the main fuse in your consumer unit.

EVs in housing cooperatives and co-ownership schemes

For a housing cooperative and co-ownership scheme, it is extremely important for the capacity of the electrical system to be evaluated before any EV charging points can be installed. These groups will need to contact a registered electrical contractor to establish the capacity and equipment required to ensure safe and stable charging in shared garages.

There are also various types of equipment available to distribute the charging time and output in garages with multiple charging outlets. This is essential if the available output is less than the current required, and would then enable all vehicles to be charged without blowing the fuses.

It is also possible to install payment systems. An electrical contractor can provide advice on which systems may be suitable, depending on your situation.

Choose the right charging equipment

Charging equipment for EVs can be divided into three categories: fast-charging, semi-fast charging and normal charging. At home, normal charging tends to be the most practical and cost efficient alternative. There are three ways to charge an EV on normal charge: Mode 1, Mode 2 and Mode 3.

Charging with a special cable (Mode 2)

The most commonly used charging equipment consists of a specially designed cable with a charging device (Mode 2) that comes with the vehicle. The charging device limits the flow of current, so that it does not draw more electricity than the vehicle and the electrical system can handle. The device also contains components that monitor safety and prevent electric shocks.

It is normally also possible to reduce the charging current manually. This means you can use Mode 2 charging equipment in a standard mains socket, without overloading the electrical system and running the risk of a fire.

It’s important that you install some kind of cradle in which the charging device can sit during charging. If you let the device dangle, this can damage the socket and cause overheating and a fire risk. If the cradle is outdoors, make sure that snow and water will not accumulate on the charging device. This could damage the equipment and increase the risk of fire.

EV without special cable (Mode 1)

If you have an older EV that doesn't have a specially designed cable with a charging device, charging can impose a high load on the circuit. Check whether your electrical system is designed for the load imposed by this kind of charging. Normally, charging via a standard mains socket is limited to a maximum of 10A, but it is often not possible to adjust this in the vehicle.

You should still make sure that the circuit is protected with an earth leakage circuit breaker. Check the socket and charging cable before every use to make sure there is no damage or signs of overheating. These signs can include yellow or brown discolouration or a burning smell in the socket. Melted plastic in the plug or socket is also a danger sign. Never use damaged equipment.

Wall-mounted charger (Mode 3)

DSB recommends wall-mounted chargers (Mode 3) with specially designed Type 2 EV charging sockets. This equipment consists of a dedicated charging device permanently mounted on the wall, and a socket that has been designed to handle a high load for extended periods. EV owners who charge their vehicles in the garage at home usually use a wired-in cable that they plug into the vehicle.

In public charging stations, you must have your own specially designed cable with a plug at both ends. The cable is locked in place during charging. The charger end of the cable has a Type 2 plug, while the plug at the vehicle end depends on the socket in the vehicle. There are two different sockets for this type of system, depending on the socket type used by your vehicle.

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