DNO Map

EV Charging and Grid Reinforcement ? - the DNO Process

17 September 2021

We have a climate emergency - zero emission vehicles, including electric vehicles, will be the only types of new cars on sale from 2030.

The UK electricity network was not designed to support the rapid uptake of electric vehicles. As such there is an urgent need for reinforcement and improvement work.

Reinforcement and improvement work is being undertaken by National Grid PLC for the high voltage national transmission network and regionally by a number of Distribution Network Operators (DNO).

As part of this reinforcement work the DNOs need to know about installations of low carbon technologies so that they can ensure that the electricity supply for these installations is adequate. These technologies include both heat pumps and electric vehicle charging equipment, both of which have to be notified to the DNOs.

Is DNO Notification Required?

Fitting of any EV chargepoint requires mandatory notification to the local DNO. Notification is undertaken using either a standard form or a spreadsheet. These are both published by the Electricity Network Association (ENA).

There are two types of notification provided for using either the ENA form or the ENA spreadsheet. These notification types are:

  1. Connect and notify

  2. Notify and connect

What is Connect and Notify?

Connect and notify is only permitted if the property maximum electricity demand is less than 60 amps including the power required by the low carbon technology to be fitted. For a 7.4kW EV chargepoint, requiring 32 amps, this means that the maximum demand of the property, pre chargepoint install, is no more than 28 amps. This is very rare!

People want their EV vehicle to be charged in a reasonable time and this demands high power. This means that the electricity demand of EV chargepoints is always high. As such the connect and notify process should almost never be used.

However, and while it is unscrupulous, many installations companies, including those owned by multi-nationals, will misinform the DNO and use the connect and notify when the maximum demand is in reality above 60 amps.

Using connect and notify guarantees quick installs. Although technically the DNO still has to be notified before the charging equipment is installed, it can be installed immediately. The DNO is then informed but the maximum demand must still be below 60 amps including the charging equipment.

For the property owner this means that the electricity supply to their home may at best not be adequate and at worst dangerous. For the DNO is means they do not in reality know what reinforcement work is needed as demand is being understated. In turn this has consequences for later low carbon technology installations and overall grid supply.

What is Notify and Connect?

Notify and connect gives the DNO the opportunity to assess if reinforcement work is required prior to the installation of low carbon technologies. It is the correct approach for most if not all EV chargepoint installations.

The notify and connect process allows the DNO to assess items such as:

  • whether the electricity supply is adequate and balanced for the local area

  • whether the electricity supply cable to the property is adequate for the demand

  • whether the supply to the property has been looped

  • whether the main service fuse in the property is adequate for the electricity use

  • whether the main service fuse installed is the same rating as that on record

This allows the DNO to determine if any reinforcement work is required whilst also alerting them to other potential supply issues that might result in injury, electric shock or fire.

If no reinforcement or other works are required the installer is informed that the low carbon technology can be installed and/or connected. This is by far the most common outcome.

Upgrading of the service fuse, normally a simple and timely visit by the DNO, accounts for the majority of all other reinforcement work. Most DNOs undertake this work for free or at low cost.

Occasionally there is either a requirement for more significant work. This may, for example, require the electricity service to be unlooped, again normally undertaken by the DNO for free. Alternatively it may be possible to reduce the maximum demand. For EV chargepoint installations this can include:

  • reducing the maximum current that the EV charging equipment can deliver

  • installing load curtailment equipment that prevents the EV chargepoint operating when other things (cookers, showers, hot tubs etc) are running

  • installing load management equipment or load managed EV charging equipment

While the DNO can ask for the low carbon technology not to be connected they are not preventing its connection. They are only specifying the reinforcement or remedial work required before the connection can be completed.

Why is Notify and Connect not always used?

The notify and connect process will always extend the time between EV chargepoint order and installation. Once notified the DNO has 10 working days to respond. This is irrespective or whether any reinforcement or remedial work is required or not.

Often the DNO will respond very quickly if no work is required but each DNO across the country works in a different way. If work is required the cost of this work or whether it is free varies from DNO to DNO. This is even if the work is a simply fuse replacement.

The time taken to do reinforcement work varies from DNO to DNO and this can add an unknown delay into when an EV chargepoint can be installed.

This inconsistency in the delay introduced by the various DNOs means some installers will routinely use the connect and notify process even when this could result in an inadequate or unsafe installation.

No installation company should try to work around the notify and connect process to avoid delays.

Can Notify and Connect Delays be overcome?

The initial 10 working days from the time of the notification cannot be overcome. The DNO may however responds more quickly than this and we have seen no action required responses within minutes of a notification being made.

If the DNO doesn't respond and 10 days passes the ENA policy is to allow the installation company to proceed with the connection.

If the DNO does respond after a connection has been made with a reinforcement work requirement it is almost always possible for the installation company to take remedial action if this is required. For example, the power output of the EV chargepoint can be lowered (permanently or temporarily) or a load curtailment device can be fitted. These actions can either avoid or work through the time required for the DNO reinforcement works.

Can the DNO prevent me having an EV chargepoint?

No. The DNO can only advise that reinforcement work or remedial action is required before an EV chargepoint can be installed. They cannot prevent you having an EV chargepoint although they can affect how much power this EV chargepoint can deliver or when it can deliver this.

Load management or load curtailment, which is rarely required, can ensure that the EV chargepoint can be used at maximum power. It will however only allow this at times when other things within the property are not also demanding large amount of power. Load management and load curtailment devices are not free or free to install although they can be very much cheaper than embarking on reinforcement work

Normally these devices never operate. EV charging is much more cheaply done at night so most users will only charge their vehicles at night. At these time not only is power cheaper but normally other high demand loads such as cookers, showers or similar are not being used. As such load management or load curtailment is not needed. It may however need to be installed to prevent everything in the property being used at the same time. This is being done to keep you and your property safe.

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