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SolarWhat a DNO is, and why it gets a say in your solar system
Your supplier sells you electricity. Your DNO owns the cables that deliver it, and it has the final say on how much generation you connect. Here is what it controls, and what it means for your design.
Updated 4 August 2026 · from the OVO Solar & Battery team
Who owns the wires outside your house
A DNO is a Distribution Network Operator. It owns and runs the regional cables and substations that carry electricity to your street and into your meter. Great Britain is carved into 14 licensed distribution areas, held between six groups, and the one covering your postcode is yours whether you like it or not. You cannot shop around for a different one.
This is a different company from the one that sends your bill. Your supplier sells you the electricity. Your DNO delivers it, maintains the physical network, and decides what may be connected to it. That is why a business you have probably never dealt with ends up with an opinion on your solar design.
Supplier and network operator are not the same thing
If your power goes off, that is a network job, and 105 is the free national number that routes you to the operator for your postcode. If your tariff is wrong, that is a supplier job. Solar sits across both, because the DNO approves the connection and the supplier pays you for what you export.
How to find yours in under a minute
Use the postcode lookup
The Energy Networks Association runs a free postcode tool that maps your address to the operator for your area.
Call 105
The same national number that reports a power cut will tell you which network operator covers you.
Read your MPAN
On your electricity bill, find the MPAN box. The first two digits of the bottom line identify your distribution area.
The one number that shapes your system
The threshold that matters is 3.68kW per phase. Most UK homes are single phase, so 3.68kW is the whole allowance. A three phase home can go up to 11.04kW on the same terms. Below the threshold, your system can be fitted and then notified. Above it, permission has to come first. On a standard installation you never touch any of this paperwork, because your installer handles it from start to finish.
The limit is on the inverter, not on the panels
It caps the inverter's AC output rating, not how much panel capacity sits on your roof. Well over 4kWp of panels on a 3.68kW inverter is the standard UK configuration, which is why the number sounds more restrictive than it is in practice.
Deliberately fitting more panels than the inverter is rated for is normal engineering, not a corner being cut. Industry practice puts the ratio of panel capacity to inverter rating between about 1.10 and 1.30. UK roofs rarely hit the lab conditions panels are rated at, so the periods where output is capped are short, and the extra panels lift your generation on winter days, early mornings and long evenings when you are most likely to use it. A battery is part of the same conversation, because it is another device that can push power onto the network.
G98 and G99, side by side
| G98 | G99 | |
|---|---|---|
| Applies when | Inverter rated 3.68kW or less per phase | Inverter rated above 3.68kW per phase |
| Three phase equivalent | Up to 11.04kW | Above 11.04kW |
| Permission before work | Not needed. Fit first, notify after | Required. Approval must come first |
| Timescale | Form submitted within 28 days of commissioning | Roughly 4 to 8 weeks, around 2 weeks on a fast track, up to 12 weeks if complex |
| Can it be refused | No, not if it is properly completed | Yes, and you have options if it is |
| Who deals with it | Your installer | Your installer |
The route is decided by the inverter's AC rating, not by how many panels go on the roof. In practice it is the difference between an installation date you can book now and one that waits on a decision, which is why a good designer settles the inverter specification early.
Get your roof, your usage and your network limit worked out on a free 45 minute video design call, with a written quote before the call ends and no home visit needed.
Get your free quote →What happens if the answer is no
A refusal is uncommon, and it is not the end of the project. The application itself is free, though some installers add an admin fee for handling it, so ask what is included before you sign anything. Our cost guide sets out what a full installation covers. Where the local network cannot take the capacity you asked for, there are four routes.
- Pay for the network reinforcement the operator has specified, which is rare and usually only worth it on larger systems.
- Cap the inverter at 3.68kW using export limitation, so the system runs on the connect and notify route instead.
- Decline the connection and keep the design as it stands for a later date.
- Reapply later, because network capacity in an area changes as the operator invests in it.
Your DNO shows up again when you get paid
Export payments need proof that the connection was notified or approved, so the network paperwork is part of the chain that gets money flowing back to you. Creating your export MPAN takes the operator roughly 1 to 4 weeks, with full onboarding usually 2 to 5 weeks after that. Signing up for OVO's export rates takes around 4 weeks and needs MCS certification or equivalent, a smart meter, and battery schematics where a battery is fitted. The conditions on each rate are set out in our export rate guide, and the sequencing of solar and storage in the solar and battery strategy.
OVO works with 16 installer businesses, selected from around 200 assessed, each holding the exclusive OVO partnership for their area. Between them they completed over 1,000 OVO solar and battery installations in the last 12 months, so the network paperwork for your region is routine to them. Find the expert for your area on the coverage page. Every installation carries the OVO guaranteed 10 year workmanship warranty.
Book your free 45 minute remote design and your regional partner will confirm which connection route applies to your home before anything is ordered.
Get your free quote →OVO SEG Install Exclusive pays up to 20p per kWh where OVO installs both solar and a battery, or 15p per kWh for solar only. The exclusive rates require you to take your electricity supply from OVO and apply to systems under 30kW. OVO's standard SEG rate of 4p per kWh is open to customers of any supplier. Rates correct at August 2026 and subject to change.
DNO questions, answered
What does DNO stand for?
Distribution Network Operator. It is the company that owns and maintains the cables, poles and substations delivering electricity to your area. There are 14 licensed distribution areas in Great Britain, held between six groups, and yours is fixed by where you live rather than by who supplies your electricity.
Who is my DNO?
Three ways to check. Use the Energy Networks Association postcode tool, call 105, or look at the MPAN box on your electricity bill and read the first two digits of the bottom line. You do not need to do any of this before booking a design call, because your installer confirms it as part of the process.
What is the difference between G98 and G99?
G98 covers inverters rated 3.68kW or less per phase. The system is fitted first and the form goes to the network operator within 28 days of commissioning, and a properly completed G98 cannot be refused. G99 applies above that rating and needs approval before the work happens. Both are handled by your installer.
How long does a G99 application take?
Usually somewhere between 4 and 8 weeks for a standard determination. Some operators run a fast track that comes back in around 2 weeks, and genuinely complex cases can stretch to about 12 weeks. Your installer will give you a realistic date for your area rather than a national average.
Can I install more than 3.68kW of solar?
Yes. The 3.68kW figure caps the inverter's AC rating per phase, not the panel capacity on the roof. Fitting well over 4kWp of panels on a 3.68kW inverter is the standard UK setup. If the inverter needs to be larger than 3.68kW, you move onto the G99 route and permission comes before installation.
Do I have to contact the DNO myself?
No. On a standard installation your installer submits and manages the notification or application from start to finish. You never fill in a form, and you are not the one waiting on hold. If you want to know where an application has got to, ask your local OVO expert.
Can the DNO stop me having solar panels?
It can decline the capacity you applied for where the local network cannot support it, which is uncommon. Even then you have options: pay for the reinforcement, cap the inverter at 3.68kW with export limitation, hold the design for later, or reapply once the operator has invested in the area.
Figures and specifications in this guide are sourced below and were checked on the date shown. Rates and product specifications change; we confirm the current picture on your free design call.
Sources
- DNO definition, the 14 licensed distribution areas, and finding yours by postcode, 105 or MPAN ovoenergy.com, uw.co.uk
- G98 connect and notify process, the 3.68kW per phase threshold and the 28 day notification window sunsave.energy
- G99 application process, determination timescales, application costs and the options after a refusal sunsave.energy
- Single phase and three phase supplies, and the 11.04kW three phase connect and notify limit ukpowernetworks.co.uk, spiritenergy.co.uk
- Inverter loading ratios of 1.10 to 1.30, clipping, and the UK convention of oversizing the array aurorasolar.com, spiritenergy.co.uk
- Export MPAN creation and onboarding timescales, and OVO SEG signup requirements and rates octopus.energy, ovoenergy.com
Read next
G98 and G99 explained: which one applies to your system
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