For most fleet charging projects, the chargers are not what sets the delivery programme. The electricity connection is.

A depot may have space for twenty charging bays and a clear case for electrification. That does not mean the local network can immediately supply the required power. The project may still need an upgraded supply, a substation or a controlled limit on demand.

This is why the DNO application should not begin after the chargers have been purchased.

A useful application starts with the fleet’s operating model. It explains the energy requirement, charging windows, existing site load and future growth. That gives the Distribution Network Operator, or DNO, a realistic connection requirement to assess.

If the existing supply has not yet been reviewed, start with our UK Fleet Depot Grid Capacity checklist before preparing the application.

What Is a DNO Application for an EV Charging Depot?

A DNO operates the regional electricity distribution network that supplies homes and businesses. It is not the company that sells electricity to the depot.

The DNO assesses whether the network can support the proposed demand. If the existing supply is insufficient, it identifies the connection work needed and issues an offer.

Depending on the site, this may involve:

• Using available capacity on the existing connection

• Increasing the capacity of an existing supply

• Installing a new electricity connection

• Connecting at a higher voltage

• Installing or upgrading a transformer or substation

• Agreeing a phased, time-profiled or flexible connection

• Completing other cable or network works

• Securing land rights for new network equipment

Smaller installations may follow a connect-and-notify or apply-to-connect route. A depot with several DC fast chargers is different. Its demand is likely to affect both the site design and local network, so the DNO should normally be involved before installation.

When Should a Fleet Depot Contact the DNO?

The best time to approach the DNO is after the first credible load assessment but before the equipment, civil design and delivery date have been fixed.

Contacting the DNO without a power requirement rarely produces a useful answer. Waiting until procurement is complete risks selecting equipment around capacity that cannot be delivered on time.

Early engagement is particularly important when:

• The existing supply has limited headroom

• Several DC fast chargers are planned

• High-energy vehicles or several high-power chargers are planned

• A transformer or substation may be required

• The fleet will be electrified in phases

• Storage, generation or V2G is being considered

• The connection date is tied to vehicle deployment

Many DNOs offer budget estimates, pre-application meetings or connection surgeries. These help test the project assumptions before detailed design.

Capacity maps are also useful for early screening. They are not a reservation or a connection offer. The DNO must still assess the actual site, requested capacity and proposed point of connection.

What Information Should Be Prepared Before Applying?

A request for “ten 150 kW chargers” is not a complete load assessment. It gives the DNO the equipment’s output ratings, but it does not explain the depot’s maximum import demand or how the charging system will operate.

A stronger application connects four areas: fleet operation, site electricity use, equipment data and the delivery plan.

1. Fleet Energy and Charging Demand

Start with the vehicles rather than the chargers.

For each vehicle group, collect:

• Vehicle type, quantity and usable battery capacity

• Typical and maximum daily energy consumption

• Expected energy remaining on return

• Arrival, departure and charging windows

• Minimum energy required before departure

• Priority routes and contingency vehicles

• Seasonal or payload-related variation

• Planned fleet additions

This work should produce two separate figures.

Energy, measured in kWh, is the electricity required during the charging period. Power, measured in kW, describes how quickly it must be delivered.

A depot that needs 4,000 kWh overnight does not automatically need a 4 MW connection. With an eight-hour window, the average requirement may be far lower. The design must still allow for losses, overlapping arrivals and priority departures.

Adding every charger’s rating can create the opposite error. Twenty 150 kW outputs total 3 MW, but an enforceable 1.2 MW site limit may prevent that demand. The team must still prove that 1.2 MW can deliver the required energy in time.

A time-based load profile should therefore show:

• When vehicles connect and depart

• Expected simultaneous charging demand

• The proposed site power limit

• How power is allocated between vehicles

• How priority vehicles are handled

• What happens during disruption

• How future fleet phases change the profile

For a broader review of the operating data needed before charger selection, see our practical fleet charging infrastructure guide.

2. Existing Site Electrical Information

The charging load must be assessed alongside everything else that uses electricity at the depot.

Prepare:

• Site address and MPAN

• Supply voltage and maximum import capacity

• Current and historical maximum demand

• Half-hourly and seasonal load data

• Transformer, switchgear and metering information

• Current single-line diagram

• Other large or potentially disturbing loads

• Planned building and operational loads

Twelve months of half-hourly data is preferable where available. A single electricity bill cannot show the shape of the site load or whether the recorded peak occurred during the proposed charging window.

The gap between agreed capacity and recorded peak demand may indicate headroom. It does not confirm that the connection is suitable. Network constraints, equipment condition and future loads also matter.

Connection applications often request capacity in kVA rather than kW. The electrical designer should use an appropriate power factor and keep the figures consistent across the application, load schedule and single-line diagram.

A Practical Equipment Example: Injet Ampax 320 kW

The charger’s DC output rating should not be copied into a connection application as though it were its AC input requirement.

For example, the ENA Connect Direct LCT Register entry for the 320 kW Injet Ampax model iNSCDA320K2P records a three-phase 400 V input, total input rated current of 510 A and total input rated power of 353.34 kVA. Its ENA system reference is INJET/10150/V1/A2.

The 353.34 kVA value matches the three-phase apparent-power calculation:

√3 × 400 V × 510 A ÷ 1,000 ≈ 353.34 kVA

The electrical designer needs this input data for the connection assessment. The 320 kW figure describes maximum DC output to the vehicle. It is not interchangeable with input kVA. Power factor, conversion losses and operating conditions still matter.

The register entry is specific to this model and reference. It should not be used to imply that every Ampax configuration has the same registered input data.

3. Charging Equipment and Control Information

The DNO may request:

• Manufacturer, model and number of outputs

• AC or DC charging type

• Rated input current and input power

• Maximum controlled site demand

• Power factor and power-quality information

• Datasheets and relevant ENA register details

• Load-management design and failure response

• Storage, generation or export information

• V2G capability where planned

If the project relies on dynamic load management, the application should explain what is being controlled.

Charger power allocation shares capacity between connected vehicles. Site load management monitors the wider depot and adjusts charging demand against a defined site limit. A project may use both functions, but they are not the same.

A proposed demand cap is only credible when the design explains what happens if communications, metering or control fails.

4. Site Plans and Delivery Information

The DNO may also need a location plan, site boundary, meter and substation positions, equipment layout, cable routes, access arrangements and connection date.

Where an agent is applying, a letter of authority may be required. If new DNO equipment will be installed on private land, identify possible wayleaves, leases, easements and access rights early. A straightforward electrical design can still be delayed by unresolved land matters.

The UK DNO Application Process for Fleet Charging

Application portals vary between network areas, but substantial fleet projects usually follow the same broad stages.

Step 1: Define the Connection Requirement

Complete the fleet load model and supply review. The output should be a maximum import requirement, time-based profile and view of future phases.

Avoid submitting several speculative applications for different capacities at the same site. If options remain open, discuss them during pre-application engagement.

Step 2: Identify the Correct DNO

Use the postcode or MPAN to identify the network operator. The ENA connection guidance includes network operator information and contact details.

Do not assume the electricity supplier shown on the bill is the DNO. They perform different roles.

Step 3: Hold a Pre-Application Discussion

Use a pre-application discussion to confirm:

• Whether the proposed capacity is realistic

• Which application route is appropriate

• Required technical documents

• Whether a new or upgraded connection is likely

• Whether alternative points of connection should be explored

• Whether a phased or flexible arrangement may be available

• What land issues could affect delivery

The aim is to expose major constraints before the formal application.

Step 4: Submit the Formal Application

Submit the requested capacity, site plans, load information, equipment data and target date.

Check that the figures match across every document. A capacity request that conflicts with the load schedule or single-line diagram will usually lead to further questions.

Step 5: DNO Assessment

The DNO may review capacity, connection voltage, point of connection, transformer requirements, power quality, protection, land rights and access.

Respond quickly if clarification is requested. A technically complex application is manageable. An application waiting for missing customer information simply loses time.

Step 6: Review the Connection Offer

Do not review the offer purely as a price.

Confirm:

• Capacity being offered

• Firm, flexible or time-profiled conditions

• Connection voltage and point of connection

• DNO and customer responsibilities

• Contestable and non-contestable work

• Equipment and civil works included

• Land and legal requirements

• Offer validity, payment and delivery assumptions

• Conditions that could change the cost or programme

An Independent Connection Provider may be able to complete some contestable design and construction work. An IDNO may also be considered. The available options depend on the project and local network.

Step 7: Coordinate Design, Construction and Energisation

After acceptance, coordinate the DNO work with depot civils, switchgear, transformers, metering, chargers and control commissioning.

The depot is not operational when the chargers arrive. The connection, site infrastructure and control system must be ready to work together.

How Long Does a DNO Connection Take?

There are two different timescales.

The first is the time needed to receive a connection offer. UK government guidance states that a DNO connection quote may take between 5 and 65 working days, depending on connection size.

The second is the time required to construct and energise the connection.

A smaller connection may be delivered relatively quickly. A depot requiring a substation, higher-voltage connection or land agreements may take many months.

Equipment lead times, planning, wayleaves, access and customer construction can all affect the programme. A quotation date is not the date the depot will have power.

What Is ENA’s Role?

The Energy Networks Association represents UK energy network operators and provides common resources for low-carbon technology connections.

It provides connection guidance, Connect Direct, network operator information and the LCT Register.

ENA does not replace the local DNO.

Connect Direct streamlines many applications and notifications. A large depot should still confirm the correct route with its DNO.

The LCT Register provides equipment information such as input ratings and power-quality data, making the proposed charger easier to identify.

Being listed is not the same as receiving approval for a particular depot. The connection still depends on site demand, the existing supply and the local network.

A charger that is not listed should not automatically be described as non-compliant. The DNO may request additional datasheets, power-quality reports or other evidence. Public product wording should say “listed on the ENA Connect Direct LCT Register”, not “ENA certified” or “ENA approved”.

Do Fleet Chargers Need G98 or G99 Approval?

G98 and G99 are associated with equipment that generates or exports electricity in parallel with the network. They are not the main route for a standard unidirectional charger that only imports electricity.

They may become relevant when a depot includes V2G, export-capable battery storage, solar generation or other equipment that can export.

In that situation, the project may have both a demand connection requirement and a generation or export requirement. They should be treated as connected parts of the same electrical design.

Can Load Management Reduce the Connection Requirement?

Load management can reduce simultaneous demand by staggering charging, reducing output during the depot’s peak and prioritising vehicles. A distributed charging system can also allocate a shared power pool between outputs where the architecture supports it.

Load management cannot increase the physical grid connection or reduce the fleet’s total energy requirement. It cannot guarantee that every vehicle will be ready unless the controlled power is sufficient for the available charging windows.

Software also does not remove the need for DNO assessment. The fleet model, electrical design and control strategy must agree.

Common Reasons DNO Applications Are Delayed

Most avoidable delays come from a small number of issues:

• The requested capacity is based only on charger nameplates

• Existing depot loads have been left out

• The equipment is fixed before the connection route is understood

• Future fleet phases are missing from the application

• Load management is mentioned without a power limit or failure response

• The application form, load schedule and drawings show different figures

• Substation space and land rights are considered too late

• The connection offer is mistaken for an energisation date

The DNO should not have to reconstruct the project logic from disconnected documents. One consistent data set should guide the application, charger procurement, site design and operating plan.

Build the Connection Around the Fleet

A DNO application is not simply a request for more electricity. It is the point where the fleet plan, electrical design and delivery programme have to agree.

Start with vehicle energy demand and charging windows. Establish the site’s existing load. Model a realistic maximum import requirement. Then speak to the DNO before the project becomes locked into a specific equipment layout or delivery date.

The result may be an upgraded supply, new connection, flexible arrangement or phased deployment. It should be based on real operating data.

Explore Injet’s commercial fleet charging solutions or contact our UK team to discuss a depot’s vehicle profile, charging windows and proposed power requirement.