Glossary of terms for Distribution Network Operators

The period to accept the connection offer from the DNO (usually around 30–90 days). Capacity is not guaranteed until payment is received and may be allocated to another applicant if not accepted in time.

DNO forms or applications used to either:

• Modify an existing supply (e.g. for additional equipment), or
• Request a completely new supply for a new building or site.

A formal document issued by a DNO outlining required works, costs, and timelines for a new or upgraded electricity connection. It becomes binding once payment is made.

A session run by your Distribution Network Operator (DNO) to discuss upcoming or planned projects.

These sessions support early engagement and help identify local capacity issues, timelines, or potential constraints before an application is submitted.

Sometimes referred to as a PACE session or DNO surgery, they can help projects plan more efficiently and reduce delays.

See also: PACE session / DNO surgery; grid constraints.

A formal submission to a DNO requesting a new or upgraded electricity connection, used to assess capacity and infrastructure needs.

A rough indication of potential costs. It is not binding and is usually based on early-stage project information.

An assessment to determine whether a proposed energy connection or upgrade is technically and economically viable.

A detailed cost estimate provided after a formal application, required to secure the works.

A formal application required for connecting generation equipment (such as solar panels or combined heat and power systems) to the grid.

Informal meetings or surgeries offered by some DNOs to support early engagement. These can clarify network capacity, timelines, and expected costs before a formal application.

*This term may also be referred to as a PACE session 

The maximum amount of electrical power your site can draw. It’s set in agreement with the DNO and determines standing charges. Can be adjusted if your site’s usage changes.

The maximum electricity output of a generator or the maximum load a grid connection can carry.

The physical linking of infrastructure to enable energy transfer between the DNO and the customer.

The capacity already available at the address in question.

The amount of electrical power used by your site or equipment. Projects that change this load, especially increases, may require DNO approval.

The main fuse protects your supply cables. If your fuse rating exceeds your cable’s capacity, the DNO may recommend changes to avoid safety risks.

A digital mapping tool used by Distribution Network Operators (DNOs) to show network information such as substations, feeders and available capacity.
GIS maps help identify where grid constraints exist and support early project planning and coordination.

See also: Grid constraints; Capacity map.

Areas of the electricity network where available capacity for new demand or generation connections is limited.
Grid constraints can affect project timelines and costs.
Each DNO provides online capacity maps and open-data portals to help identify these areas before submitting an application.

See also: GIS (Geographic Information System); Sufficient capacity.

Electrical infrastructure operating above low-voltage levels (typically above 1 kV), such as transformers, switchgear and cabling.
This equipment is required for larger heat-pump, solar PV or battery installations.
HV connection equipment can be eligible for Salix funding if it is essential to deliver the approved project scope.

See also: Transformers; 

The amount of electrical power being used or required at a given time.

Indicates that no additional works are needed because the substation already has the capacity for the increased demand.

The total capacity needed after an upgrade.

Devices that change voltage levels, typically reducing high transmission voltages to lower levels for homes and businesses.

Parts of a grid connection that can be completed by an independent contractor rather than the Distribution Network Operator (DNO).
Using external contractors can reduce costs but means the organisation is responsible for managing delivery, quality and compliance.
Choosing the DNO to carry out all works provides a single point of accountability and can reduce project risk.

See also: Non-contestable works; Independent Connection Provider (ICP).

A provider offering services across electricity, gas, water, and telecommunications.
These contractors can streamline delivery but require careful coordination with network operators and project teams.

Work that must be completed by the DNO or their appointed agents (e.g. ICPs), such as connecting to the substation.

A permit issued by a local authority allowing a licensed organisation to undertake excavation or works in a public highway.
It is required if a contractor, rather than the DNO, applies for a road closure or carries out connection works on public land.
If a contractor does not hold a Section 50 licence, the DNO will usually submit the road-closure application.

See also: Contestable works

A change to existing electrical infrastructure, such as moving or reinstalling cables during retrofit works like external wall insulation.
These are not treated as new connections. Early engagement with your network operator is recommended to avoid delays and ensure safety compliance.

A licensed company that distributes electricity in a specific region of Great Britain. DNOs own and operate the infrastructure from the transmission network to homes and businesses.

An industry initiative led by Ofgem and the Energy Networks Association (ENA) to simplify and standardise the grid-connection process across all DNO regions.
The programme aims to improve consistency in forms, terminology and connection timelines, helping projects move from application to delivery more efficiently.

See also: Ofgem; The Energy Networks Association.

An accredited company that can build electricity networks to the standards required for ownership by DNOs or IDNOs.

A licensed company that owns and operates local electricity networks connected to the main distribution network.

The organisation responsible for managing Great Britain’s electricity transmission system and long-term energy planning.
NESO coordinates with DNOs where large-scale generation or demand projects may affect the wider transmission network, ensuring local and national systems remain balanced and secure.

The regulator for electricity and gas markets in Great Britain. DNOs are regulated by Ofgem.

A not-for-profit body representing companies that operate energy networks in the UK and Ireland. Maintains an approved appliances database and supports customer connections.

Small-scale technologies that generate and store electricity near where it will be used.

Infrastructure that takes electricity from the transmission network and smaller generators and delivers it to homes and businesses at low voltage.

The high-voltage transmission network that moves electricity across long distances before it reaches local distribution networks.

Data related to the historic, current, and future operation, performance, and usage of the electricity network.

A facility that houses equipment like transformers and switchgear, used to step down voltage and manage power flow.

Moves large amounts of electricity over long distances at very high voltages.

A project that has secured grid-connection capacity but has shown no progress or communication for an extended period.
Under Ofgem’s Clean Power 2030 reforms, such connections are being reviewed to release unused capacity.
Active and progressing projects are not affected.

See also: Capacity; Ofgem.

A unique number (21 digits) that identifies your electricity supply point. Found on your electricity bill and required for supply changes.

A unique number (up to 12 digits) assigned by local authorities to each land or property in the UK.