Do I need DNO approval (G98/G99) for solar?
Yes, your solar installation must be notified to your Distribution Network Operator (DNO), but your installer handles this. Smaller systems up to 3.68kW per phase use the G98 process, where the DNO is simply notified after install. Larger systems need G99 approval before connecting, which can add a few weeks to the timeline.
G98 vs G99 in plain terms
- G98: systems up to 3.68kW per phase; install first, notify the DNO after.
- G99: larger systems; the DNO must approve before connection.
- Your installer submits the paperwork as part of the job.
- G99 approval can take a few weeks, so factor it into your timeline.
Why it exists
The DNO manages the local electricity network and needs to know about systems that feed power back into it, to keep the grid stable and safe. For most homes this is a background formality your installer takes care of.
Frequently asked questions
- Will G99 approval delay my install?
- It can add a few weeks for larger systems, as the DNO must approve before connection. Smaller G98 systems have no such wait.
- Do I need to contact the DNO myself?
- No. A competent MCS installer handles all DNO notification and approval on your behalf.
Related questions
Indicative estimates based on UK average data. Last updated 27 May 2026.