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DNO Renewables
Applications1 min read

What is G100 and when do I need it?

G100 is the technical standard for export limitation. Here is when it comes into play.

Written by the DNO Renewables teamUpdated

What G100 is

G100 is the Engineering Recommendation from the ENA (Energy Networks Association) that defines how export limitation must be implemented. It is the technical rulebook for capping how much a system can export to the grid.

When it applies

[!INFO] You need a G100-compliant setup any time the export capacity you want to allow is less than the total generation capacity of the system.

Common examples:

  • 10 kW solar array with a 3.68 kW export cap (very common for domestic)
  • 5 kW inverter with a battery, exporting only 3.68 kW
  • Large commercial solar with export capped to protect the local network

The G100 requirements

  1. An export limitation device that can throttle the inverter in real time
  2. A CT clamp on the main incoming supply to measure export
  3. Response time under 5 seconds when export is detected
  4. Failsafe: if the device fails, the inverter must stop exporting

The paperwork

A G100 application typically involves:

  • Completed G100 form (we handle this)
  • SLD showing the CT clamp position
  • Datasheet for the export limitation device
  • Commissioning proof that the limit was tested

Common kit

  • Fronius Smart Meter
  • SolarEdge Home Wave
  • SolaX X3-EPS export CT
  • Sunsynk export CT setup
  • Standalone: SolarEdge Zero Export, Reactive Technologies

[!WARNING] Not every inverter's built-in "export limit" mode is fully G100 compliant. Check with the manufacturer and confirm the model before quoting.

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