Ireland Esb Networks Nc6 And Nc7 Solar Interconnection Guide

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Key Takeaways

• Form NC6 governs micro-generation up to 6 kVA single-phase and 11 kVA three-phase under a zero-cost 'inform and fit' notification procedure.
• Form NC7 covers mini-generation up to 17 kVA single-phase and 50 kVA three-phase, requiring formal technical studies taking 8 to 10 weeks.
• All micro-generation inverters must comply with standard IS EN50549-1 with current Irish settings and be installed to Safe Electric standards.
• For commercial systems above 50 kVA up to 200 kVA, Form NC8 applies with a mandatory external G10 Protection Relay and EGIP witness testing.
• ESB Networks targets smart meter installations within four months of processing a valid NC6 notification.

The Three Interconnection Tiers in Ireland

ESB Networks categorises distributed renewable energy installations into three distinct Low Voltage (LV) connection tiers based on export capacity and inverter rating:

Micro-Generation (Form NC6): The Inform and Fit Process

Under statutory rules, a micro-generator is a source of electrical energy which operates in parallel with ESB Networks LV System and rated up to and including:

• 25 amperes (≈6kVA) at low voltage when the connection is single phase
• 16 amperes (≈11kVA) at low voltage when the connection is three-phase

Key operational parameters for NC6 include:

1. Zero Connection Charge: There is no charge to connect a Micro-generator to the ESB network provided it is Micro-generation which can be connected under the 'inform and fit' process i.e. up to 6kVA single phase or 11kVA three phase.
2. Quality Compliance: The generator (inverter) must comply with IS EN50549-1 with current Irish settings. Installers must submit an accredited type test certificate.
3. Electrical Contractor Accreditation: It is your responsibility to ensure that the Micro-Generator is installed by a registered electrical contractor to Safe Electric standards.
4. Smart Metering Deployment: Where customers are eligible to have a smart meter installed during this phase of the rollout, ESB Networks endeavours to install a smart meter within four months of a valid NC6 form being processed by ESB Networks.

Mini-Generation (Form NC7): Commercial Systems up to 50 kVA

When rooftop installations exceed the 11 kVA three-phase microgen threshold, projects transition into mini-generation:

• Capacity Scope: Inverter systems from 25 amperes (6kVA) to 72 amperes (17kVA), when the connection is single-phase, and 16 amperes (11kVA) to 72 amperes (50kVA), when the connection is three-phase.
• Technical Governance: Projects are evaluated under Conditions governing connection operation mini-generation.
• Assessment Timelines: Because larger installations impact local transformer capacity, the average timeframe for the connection offer documents to issue is 8 to 10 weeks from payment of the application fee.

Small-Scale Generation (Form NC8): Systems from 50 kVA to 200 kVA

For large commercial roofs, warehouses, and agribusinesses deploying arrays above 50 kVA:

• Scope: Inverter-connected installed capacity greater than 72amps (≈50kVA) Three Phase and up to 200kVA, or synchronous installed capacity greater than 6kVA and up to 200kVA.
• Mandatory G10 Interface Relay: A G10 Protection Relay is mandatory in all installations under the Small Scale Generation Scheme, providing fail-safe loss-of-mains disconnection.
• Witness Testing: Prior to energisation, developers must contact ESB Networks at egipwitnesstesting@esb.ie, prior to energisation, to arrange EGIP Witness Testing.