Grid capacity and DNO approval for EV chargers

Who your DNO is

Your electricity supplier sells you power. Your distribution network operator (DNO) owns the cables, substations and the main fuse that bring it to your building. Across the North East, that's Northern Powergrid.

The DNO needs to know about EV chargers because they can add a large load. Sometimes it just needs telling. Sometimes it needs to approve the connection first. This is one of the steps covered in how our installation works, and it's often what sets the timetable.

Holiday parks and rural sites should look at this early, because any network work has to be designed and quoted before it can be booked.

Reading your own supply

A few terms come up again and again.

• Single-phase or three-phase. Smaller premises tend to have single-phase, which tops out at 7.4kW for a charger. 22kW AC charging needs three-phase at 32A per phase (bestchargers.co.uk).
• Cut-out rating. The cut-out is the DNO's sealed fuse where the supply enters the building. Its rating, in amps, is the ceiling for what you can draw.
• Maximum demand. The most power your site uses at its busiest moment. In a hotel, that's often a winter evening with the kitchen, laundry and heating all on.
• Metering. Smaller sites have a whole-current meter. Larger sites have CT metering and an agreed maximum import capacity, often quoted in kVA.

Here's why it matters. Our dual 22kW charger has two sockets. If both ran at full power, that's 64A per phase on top of whatever the building already uses. On many supplies, that won't fit without help.

Connect and notify, or apply to connect

The DNOs share a national form for EV chargers and heat pumps, published by the Energy Networks Association (ENA EVCP and HP form, v3.3). It sets out two routes.

Connect and notify

The installer connects the charger, then tells the DNO within 28 days. This only applies if all of these hold:

• only one additional charger or heat pump is being added
• the cut-out rating is known and the service is in sound condition
• the site has a metered supply and isn't on a looped service
• maximum demand stays below the cut-out rating
• maximum demand stays below 13.8kVA (60A) per phase, unless the premises is CT metered or the load is limited

For CT-metered premises, the form adds a further test. The chargers' maximum AC output must be no more than 30% of the site's maximum import capacity.

Apply to connect

If any of those can't be ticked, you must apply to the DNO before the charger is connected. A dual 22kW pedestal draws a lot of power, so many sites end up here unless the load is limited.

Applying doesn't mean an upgrade is needed. Often the DNO checks the network, confirms there's room and the job carries on.

How long the DNO takes

The response time depends on the size of the load and how much network work is involved.

The quote timescales above 100A come from the national Guaranteed Standards of Performance (ENWL Notice of Rights, April 2025). They cover getting a quote, not doing the work. If the network needs upgrading, the works themselves take longer.

We can't give you Northern Powergrid's current lead times for works. They vary by job and by what's happening on the local network.

Where no major network work is needed, our installs typically take 6–12 weeks from survey to switch-on. A grid upgrade can push that out.

What a survey checks

The DNO form asks for details that only a site visit can give. At the survey we look at:

1. The cut-out. Its rating and condition. If the rating isn't marked, the DNO can confirm it. Nobody should open the cut-out unless authorised.
2. The meter. Whole-current or CT metered, and the agreed capacity if there is one.
3. Maximum demand. A load survey of what the building already draws, plus the new chargers. The form says this is required to calculate maximum demand.
4. Phases. Whether three-phase is available where the chargers will be fed from.
5. Earthing. The form asks for the earthing arrangement, such as TN-C-S (PME), TN-S or TT. It affects how the charger has to be protected.
6. The distribution board. Whether there's space and capacity for a new circuit.
7. The cable route. How far it is from the board to the bay, and what's in the way. Longer trench runs add cost, which our installation cost guide covers.
8. Data connection. The charger talks to the back office for payments and monitoring, so we check signal or network access at the bay.

Avoiding an upgrade with load management

The cheapest way through the grid question is often not to need more power at all. Load management lets the chargers use whatever capacity the building isn't using, and turns them down when it is.

The ENA form treats a limited load differently from an unlimited one. Limiting the chargers so total demand stays below the cut-out rating can change which route applies, although the DNO still makes the final call.

Most charging at hotels, venues and parks happens in the evening and overnight, when much of the building is quiet. That's when load management has the most room to work. Our load management guide explains how it shares the supply, with a worked example.

When an upgrade is worth it

Sometimes load management isn't enough. If you want several pedestals and your busiest hours clash with peak charging, a bigger supply may make sense.

An upgrade means a quote from Northern Powergrid, and the cost depends on how much network work is needed. Get that quote before you commit, and compare it with a smaller first phase that fits your current supply. Process details and costs can change, so check the current position with the DNO before relying on any figure.

Next step

The quickest way to know where you stand is a free site survey. We'll check your supply, tell you which DNO route applies and handle the application. To see how supply work affects the numbers, compare our packages.