The one-line version
- Import = electricity flowing from the grid to the property (using electricity)
- Export = electricity flowing from the property to the grid (selling solar back)
Why installers mix these up
Because the DNO cares about both, and the paperwork lists them separately.
When each matters
Import capacity matters when
- You're installing EV chargers, heat pumps, or big loads
- The customer wants to upgrade their supply from 60A to 100A (a "supply upgrade")
- You're on a fuse that would blow with the added load
Export capacity matters when
- You're installing solar, wind, or battery with export
- The customer wants to feed back to the grid
- You're applying for a Smart Export Guarantee tariff
Typical numbers
| Property | Import (typical) | Export requested (typical) |
|---|---|---|
| UK domestic house | 60A or 80A single phase | 3.68 kW to 5 kW |
| Large domestic | 100A single phase | Up to 16 A single phase |
| Small commercial | 3-phase 100A | Depends on system |
| Large commercial | 3-phase 200A+ | 30 kW+ |
On the DNO application
You'll be asked for both:
- Existing import capacity (from the customer's cut-out or fuse rating)
- Requested export capacity (usually the inverter's AC rating, or lower if export-limiting)
[!TIP] A customer with an EV charger and solar is asking the DNO for both an import capacity confirmation and an export approval at once. That's normal and it's still one G99 application.