Be prepared - planning & DNO (G98/G99/G100) considerations

Solar panel installation

• Typically installing rooftop solar panels do not require planning permission for a first installation, however there are exceptions e.g. living in or next to a conservation area, main roads etc. so check with your local authority if you are unsure.
• Adding panels to an existing standalone installation later requires planning permission as only the first standalone installation is exempt.
• Larger modern solar panels can weight between 18-26kg or more. Have a roof structural check done to ensure the roof can handle the snow and wind loads. Have a layout plan drawn up to ensure correct spreading of the loads across the roof and mounting points.
• As a guide, solar panels should not be installed closer than 400mm from a roof edge. This is due to water runoff issues, wind noise and lift factors.
• While planning rules may vary slightly depending on your location, panels should not protrude above the roof line. Double check the local rules regarding this especially for flat roofs. 
• Ground mounted panels may require planning permission and can be subject to maximum allowable surface limitations and other rules, so always check.
  

DNO - Grid connectivity basics

• G98 requires a notification within 30 days of installation if the generation < 16A per phase (3.68kW)
• G99/100 requires an application and approval, before any installation can be done, if the generation > 16A per phase.
• For the typical G99 domestic type A installation, abbreviated or fasttrack applications are available from your DNO.
• The generation equipment (inverters, micro inverters, and AC-coupled storage with integrated inverters) connected to the grid has to be be fully G98/G99 type tested and certified. The ENA register lists products submitted for validation by manufacturers and their status.
  
• For any change/upgrade to existing systems, the DNO has to be notified or a relevant application submitted as necessary.
• Commissioning test documents also has to be submitted to the DNO.
• For larger G99/G100 compliant  systems, the DNO may require feedin limiting devices to be fitted which could be costly in terms of the hardware and the DNO's involvement.

DIY electrical connections (caution advised)

• Competent DIY'ers can install a system if there is an existing dedicated spare circuit and switch of the required capacity.
• If a new circuit is required, a competent DIY'er can do the installation, BUT it cannot be commissioned until it has been tested and signed off by a qualified electrician as it is a Part P notifiable activity.
• All the work carried out must comply with the latest building Part P regulations and tested accordingly before commissioning.
• A lockable double pole isolation switch has to be installed between the equipment and mains supply and the necessary warning labels displayed on all equipment.
• Always seek professional advice if unsure as people's lives could be put at risk and home insurance policies potentially invalidated.