DNOs: Who is my distribution network operator?

A short guide to DNOs and what they do

A Distribution Network Operator (or DNO) is a company licensed to distribute electricity in the UK. These companies own and operate the system of cables and towers that bring electricity to our homes and businesses.

Most of us know about the companies that supply electricity to homes (such as OVO). But many of the companies involved in the distribution of energy to UK homes and businesses are largely unknown to the public. In this guide we’ll look at who they are, and what they do.

What is a Distribution Network Operator (DNO)?

You might be surprised to learn there are actually 4 different types of businesses involved in keeping our lights on and our homes warm. Here’s a quick summary of the sectors that run our power network:

1. Generation: responsible for power plant ownership and operation
2. Transmission: responsible for high voltage transmission networks
3. Distribution: responsible for local distribution via towers, cables and meters
4. Suppliers: electricity sellers like OVO

Distribution Network Operators are responsible for the distribution of electricity from the national grid to your home or business. Since they look after the network of towers, transformers, poles, cables and meters that deliver power to your home, they’re also the people to call if there’s a power cut. 

By the way, in case of a power cut, call 105 (free from most landline and mobile numbers) to be put straight through to your local District Network Operator.

DNO regions and operators

In Great Britain there are 14 different district networks or DNO regions. However, because these 14 regions are managed by just 6 operators, it’s relatively simple to work out yours.

DNO map: find your local DNO supplier

Check the map below from the Energy Networks Association to see where each DNO operates.

DNO by postcode

If you’re not sure who you should call from the map above, simply enter your postcode here to find out.

District Network Operator solar connection

Whenever you connect any type of electricity generation to the grid, you need to inform your local Distribution Network Operator (DNO). In general, this isn’t a big issue – but if you’re connecting a home solar system, be aware that your responsibilities will change, depending on the size of the system you’re installing. Any installer registered with the Microgeneration Certification Scheme should be well aware of these details, but it's worth knowing the following: 

Smaller systems

If you’re connecting a small system (up to 16A per phase or 3.7 kW), your installer just needs to inform the DNO within 28 days of the system’s commissioning. Small systems are unlikely to result in load issues for the local grid – so the regulation is relatively simple.

Larger systems

For bigger systems, your installer will need permission from the DNO in order to connect to the grid. In many cases, this will require a network study (which you may be charged for), to check that the local grid network is adequate for the power your system will produce. If the grid needs additional work to cope with the energy from your system, the DNO is required to provide you with a quote for the work within 45 days.

Keen to learn about the solar revolution, from how they work, to how they could power your home? Learn more about solar panels here.

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