A clear comparison of the NC6, NC7, and NC8 ESB Networks forms for Irish solar PV installers — capacity thresholds, the inverter kVA vs panel kWp distinction, and when each form applies.
ESB Networks requires micro- and small-scale generators connecting to the Irish distribution network to notify ESB Networks before energisation. For solar PV systems, there are three notification forms. The correct form depends on the inverter capacity in kVA and the number of phases of the connection:
| Form | Phase | Capacity Range | Typical Use | Process |
|---|---|---|---|---|
| NC6 | Single | Up to ~6 kVA (25A) | Residential solar | Notification only — no approval needed |
| NC6 | Three | Up to ~11 kVA (16A/phase) | Residential solar | Notification only — no approval needed |
| NC7 | Single | 6 kVA – 50 kVA | Large residential / small commercial | Application + ESB Networks assessment |
| NC7 | Three | 11 kVA – 50 kVA | Small commercial | Application + ESB Networks assessment |
| NC8 | Three | 50 kVA – 200 kVA | Commercial / industrial | Application + technical assessment |
The vast majority of Irish residential solar installations fall under the NC6. A typical domestic system — 10–16 panels, 4–6.6 kWp, single-phase inverter rated 3.6–6 kW — will almost always have an inverter output below 6 kVA.
But there are edge cases, and choosing the wrong form delays connection approval. This guide clarifies which form you need and why.
Key note: The NC6 is a notification only — there is no fee and no approval step required before installation. You must submit it, but you do not wait for ESB Networks to approve it before energising the system. The NC7 and NC8, by contrast, require an application with an assessment by ESB Networks, and may involve fees and waiting periods.
The threshold that determines which form to use is the inverter's rated AC output in kVA, not the panel array's DC capacity in kWp. This is the most important and most frequently misunderstood aspect of NC form selection.
Why this matters:
Consider a 6.6 kWp solar system (e.g., 16 × 415 W panels). This is a common configuration — slightly oversized relative to the inverter to maximise generation in lower irradiance conditions. The inverter might be rated at 5 kW / 5 kVA AC output. In this case, despite the panel capacity exceeding 6 kWp, the inverter output is 5 kVA — below the NC6 threshold. The NC6 is the correct form.
Conversely, a 5.5 kWp system with a 7 kVA three-phase inverter (which might be installed for three-phase load balancing at a farm or small commercial) would require the NC7, not the NC6, despite the lower panel wattage.
The rule:
The NC6 Microgeneration Notification covers the vast majority of domestic solar PV systems. It is submitted to ESB Networks by the SEAI registered installer after commissioning, by post.
When NC6 applies:
Key requirements:
The NC7 (Mini-generation Application) covers:
This is the territory of:
The NC7 process differs from the NC6 in a critical way:
The NC7 is a notification with potential for assessment, not simply a post-installation notification. ESB Networks may undertake a technical review of the proposed connection. This can add several weeks to the timeline. For very large systems toward the upper end of the NC7 range (e.g., 40–50 kVA), there may be network capacity constraints that require resolution before connection can proceed.
Practical implication for installers: If you are working on a three-phase agricultural or small commercial installation where the total inverter output exceeds 6 kVA, clarify with ESB Networks' Microgeneration or Small-Scale Generation team at the outset whether pre-connection discussions are recommended. Do not assume the process is as simple as the NC6.
The NC8 covers systems from 50 kVA to 200 kVA — medium-scale commercial and light industrial solar:
NC8 process:
NC8 installations are outside the scope of the SEAI residential Solar PV grant (which applies to much smaller domestic systems).
Work through this decision in order:
Find the inverter's rated AC output in kVA. This is on the inverter datasheet and nameplate. For most single-phase inverters, kW ≈ kVA (unity power factor). Do not use the panel kWp figure.
For three-phase systems, consider the total inverter output across all phases. A three-phase inverter rated 10 kW produces 10 kVA — this is an NC7.
Apply the threshold:
6 kVA to ≤50 kVA → NC7
50 kVA to ≤200 kVA → NC8
If uncertain, contact ESB Networks before submission. Submitting the wrong form causes delays and may require resubmission.
Solar PV systems are sized and sold in kWp (kilowatt-peak, a DC power rating for panels under Standard Test Conditions). But ESB Networks' connection thresholds are based on kVA (kilovolt-ampere, an AC power rating for the inverter output).
The two numbers are related but not identical:
A 5 kWp panel array connected to a 4.6 kW inverter has a DC:AC ratio of 1.087. This is a standard engineering choice — slightly oversize the panels relative to the inverter to extract more energy during low-irradiance conditions.
In this case: 5 kWp panels → 4.6 kW / 4.6 kVA inverter output → NC6.
A 48 kWp commercial system with a 30 kW three-phase inverter: 48 kWp panels → 30 kVA inverter output → NC7.
When filling in any of the NC forms, always ensure:
The NC6 guide covers these fields in detail →
For the majority of domestic residential installations — 8 to 16 panels, 3.5 to 6.6 kWp, single-phase inverter rated 3–6 kW — the answer is NC6. Always confirm by checking the inverter's rated AC output on the datasheet.
Reserve NC7 for farm/commercial three-phase systems and larger agricultural buildings. NC8 is for genuinely large commercial installations with inverters above 50 kVA.
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