Contestable vs Non-Contestable Works

The Basic Distinction

When a new electricity connection is required, for a housing development, a commercial site, a renewable energy project or any other new connection, some of the required works can be opened up to competitive tender by an ICP, and some must be carried out by the DNO itself. This is the contestable/non-contestable distinction.

Contestable works are those that a developer or their appointed ICP is permitted to carry out instead of the DNO. The ICP installs the infrastructure to DNO standards, and it is then adopted into the distribution network. Because ICPs compete for this work commercially, prices are competitive and programmes can often be faster than going direct to the DNO.

Non-contestable works are those that only the DNO is permitted to carry out, typically works on the existing live distribution network at the point of connection. These are priced and delivered by the DNO on a cost-plus basis with no competitive alternative.

What Is Typically Contestable?

Design of the new connection infrastructure
Installation of new HV cables from the point of connection to the new substation
Installation of the new substation and all associated fit-out, earthing, small power, LV STC panels, metering
Installation of the LV network from the substation to the supply points
Testing and commissioning of the new infrastructure
Adoption support and DNO audit attendance

This is broadly the scope that R&D Cable Jointing delivers, HV jointing, substation installation, LV works and testing, as a specialist subcontractor to the ICP.

What Is Typically Non-Contestable?

Physical connection of the new infrastructure to the existing DNO network, for example, jointing into an existing DNO cable, connecting into a ring main unit or substation busbar
Any switching operations required on the live DNO network to facilitate the connection
Network reinforcement required to provide sufficient capacity at the point of connection, for example, upgrading a section of existing DNO cable that has insufficient capacity for the new load
Installation of new DNO metering equipment
Formal energisation of the new connection under the DNO's own safety management system

Why Does This Matter for Your Project?

Budget: contestable works can be competitively tendered, so you have genuine commercial control over a significant part of the connection cost. Non-contestable works are priced by the DNO and are not negotiable in the same way.

Programme, the DNO's non-contestable programme, particularly network reinforcement, can be a project-critical path item that is entirely outside your control. Understanding early whether reinforcement is required, and what the DNO's programme looks like, is essential for realistic project programming.

Quality and accountability: for the contestable scope, you are responsible for selecting an ICP and a jointing contractor whose work will meet DNO standards. A failed test, a poor installation or a joint that fails in service creates costs and delays that sit with you as the developer. This is why the quality of the HV jointing contractor matters.

The Contestable Connection Process

Application: the developer or their agent applies to the DNO for a connection offer. The DNO issues a connection offer specifying the point of connection, the non-contestable works required and the charges for those works.
ICP appointment: the developer appoints an ICP to design and deliver the contestable scope. The ICP prepares a design to the DNO's standard and obtains approval before work commences.
Installation, the ICP and their subcontractors install the contestable works, HV cable, substation, LV network. R&D Cable Jointing delivers the HV jointing and substation fit-out at this stage.
Testing and commissioning: the new infrastructure is tested, the DNO witnesses commissioning and the installation is approved for adoption.
Connection day: the DNO carries out the non-contestable connection works on its network. The IDNO (or DNO) formally adopts the new infrastructure. R&D Cable Jointing as SAP takes control of the new LV network on behalf of the IDNO.
Energisation: the new connection is energised and the supply is live.

Contestable Works and DNO Standards

Although contestable works are carried out by an ICP rather than the DNO, they must be designed and installed to the DNO's own engineering standards. UKPN, SSEN, NGED and the other DNOs each have their own detailed engineering standards covering cable specification, joint types, substation fit-out, testing and commissioning. The ICP and their subcontractors must demonstrate compliance with these standards, which is why DNO authorisations and experience of working to DNO specification matter when selecting a jointing contractor.

R&D Cable Jointing holds UKPN authorisations and has delivered HV jointing and substation works to the specifications of multiple DNOs across our operating area. We understand what DNO auditors look for and ensure our work is documented and presented to support a smooth adoption process.

FAQs

Your questions answered

Can the HV cable installation be contestable?

Yes: the installation of new HV cables from the point of connection to the new substation is generally contestable, meaning an ICP can install it rather than the DNO.

Who does the final connection to the DNO network?

The physical connection to the existing DNO live network is non-contestable, the DNO carries this out on connection day. The ICP installs everything up to (but not including) that connection point.

Does the DNO need to approve the ICP's design?

Yes: the ICP's design must be approved by the DNO before installation work begins. The DNO will also witness testing and commissioning before adoption.

What happens if the DNO requires network reinforcement?

Network reinforcement required on the existing DNO network to provide capacity for the new connection is non-contestable, the DNO carries it out and charges accordingly. This can be a significant programme risk if the reinforcement is on the critical path and has a long DNO lead time.

What is NERS accreditation?

NERS (National Electricity Registration Scheme) is the accreditation framework for ICPs. To carry out contestable connection works, an ICP must hold the relevant NERS accreditations for design, installation and testing.