The answer depends on the size of the system. For most domestic solar panel installations in Devon, a 4kWp system on a 3 or 4-bedroom home, DNO approval is not required in advance. But it is not quite that simple, and getting the answer wrong on a larger installation has real consequences. Here is the complete picture.
What is a DNO?
DNO stands for Distribution Network Operator. DNOs are the companies that own and operate the electricity distribution network in each region of the UK, the cables, substations, and transformers that carry electricity from the national grid to homes and businesses. In Devon and Cornwall, the DNO is Western Power Distribution (now trading as National Grid Electricity Distribution). In parts of Somerset and the wider South West, coverage may differ.
When you install solar panels or a heat pump, you are connecting a generating or consuming device to the DNO’s network. The DNO needs to know about significant connections to manage the network safely and effectively. That is what DNO approval or notification is about.
The G98 and G99 thresholds
G98 – notification, not approval
For domestic solar panel installations up to 3.68kW (16A single phase), the process is a G98 notification. This means the installer notifies the DNO that the installation has taken place, within 28 days of commissioning. It is not an approval process — the DNO does not need to say yes before you can install. M&E Contrax submits the G98 notification on your behalf as part of every qualifying installation.
G99 – full application required
For systems above 3.68kW single phase, which includes most commercial solar systems and larger domestic systems of more than around 12 to 16 panels, a G99 application is required before installation begins. The DNO reviews the application and confirms whether the local network can accommodate the export capacity. G99 applications typically take 20 to 65 working days to process, though the DNO may respond faster in straightforward cases.
For most Devon domestic solar installations of 4kWp to 6kWp, the installed capacity exceeds the 3.68kW G98 threshold, which means a G99 application is technically required. In practice, many installers submit a G98 notification for these systems rather than a G99 application, which is a grey area worth understanding. M&E Contrax always confirms the correct application route for each installation at the survey stage.
Export limitation as an alternative to G99
Where a G99 application might be rejected or delayed due to local network constraints, an export limitation device can be installed. This caps the export from your solar system to 3.68kW, allowing a G98 notification to be used instead of a G99 application even for a larger system. The panels still generate at full capacity for self-consumption, only the export to the grid is capped.
For Devon commercial properties in areas with constrained grid capacity, export limitation is often the most practical route to getting a larger system installed without the G99 process timeline.
Do heat pumps need DNO approval?
Heat pumps connect to the grid as consuming devices rather than generating devices. A domestic heat pump installation typically does not require a DNO application, though for very large heat pump systems in properties with limited incoming supply capacity, a supply upgrade may be needed. We assess the supply capacity at every survey.
Commercial solar PV combined with heat pumps, for example, a commercial building installing both solar and a large heat pump system, may require a more detailed G99 assessment covering both the export from the solar and the additional demand from the heat pump. We manage this assessment as part of every combined installation.
How long does DNO approval take in Devon?
G98 notifications are submitted by the installer after commissioning and require no response from the DNO, they are informational. There is no wait time.
G99 applications are assessed by National Grid Electricity Distribution and can take anywhere from a few weeks to several months depending on local network capacity, the size of the installation, and whether a technical assessment is required. For a straightforward domestic system requiring a G99 application, four to eight weeks is a reasonable expectation. For larger commercial systems in areas with constrained networks, it can take considerably longer.
M&E Contrax submits all DNO applications and tracks progress on your behalf. We build the expected DNO timeline into the project programme at the quote stage so there are no surprises.
What happens if you install without the right DNO notification?
Installing without a required G99 application, or failing to submit a G98 notification within 28 days, can cause problems with your MCS certification, your Smart Export Guarantee eligibility, and your building insurance. The MCS installer is responsible for the correct notification, not the homeowner, but if an installer has not followed the correct process, it falls to the property owner to resolve.
Before choosing an installer, confirm that they handle all DNO notifications and applications as part of the installation. M&E Contrax manages every DNO submission for every Devon installation we carry out.
Book a free solar survey in Devon
Call 01364 654271 or contact us online. DNO applications managed as part of every M&E Contrax installation.
MCS Accredited | NICEIC Approved | Newton Abbot, Devon | 20 miles from Dartmouth
Written by Lee Bullingham, Solar PV Installation Lead, M&E Contrax Renewables. Published September 2026.
Do solar panels need DNO approval?
For installations up to 3.68kW single phase, a G98 notification is submitted after installation, no advance approval is needed. For systems above this threshold, a G99 application must be submitted and approved before installation begins. Most domestic solar systems in Devon fall into the G99 category. M&E Contrax handles all DNO submissions on your behalf.
What is the difference between G98 and G99 for solar panels?
G98 is a post-installation notification for systems up to 3.68kW, no DNO approval needed in advance. G99 is a pre-installation application for larger systems where the DNO must confirm the local network can accommodate the export. G99 applications typically take 20 to 65 working days.
How long does a DNO solar application take?
G98 notifications require no response from the DNO and have no waiting time. G99 applications are typically processed in four to eight weeks for straightforward domestic systems. Larger commercial systems or installations in areas with network constraints can take longer. We build the expected DNO timeline into every project programme at the quote stage.
Do commercial solar PV installations need DNO approval?
Yes. Commercial solar systems are almost always above the G98 threshold and require a G99 application before installation. For large commercial systems, a detailed technical assessment may be required. M&E Contrax manages the G99 application and technical assessment process for every commercial installation we carry out in Devon.
Do heat pumps need DNO approval?
Domestic heat pump installations typically do not require a DNO application. For commercial installations or properties with limited incoming supply capacity, a supply assessment may be needed alongside the heat pump installation. We confirm the requirements at the survey stage for every heat pump project.
Does M&E Contrax handle the DNO application?
Yes. We manage all G98 notifications and G99 applications for every solar installation we carry out in Devon. You do not need to contact the DNO directly. We track application progress and update you at every stage.
