Most commercial solar panels in Greater Manchester do not need a planning application. Solar on the roof of a business building in England is permitted development under Class J of the General Permitted Development Order, so a system up to 50 kW goes ahead without the council, and a bigger roof system needs only the council's prior-approval decision on how it looks. The exceptions are listed buildings, ground-mounted arrays and carports. This guide takes each case in turn, using the national rules and the way the ten Greater Manchester councils apply them. If you are weighing up a system, our page on commercial solar panels in Manchester covers yield, the grid connection and tax alongside planning.
The short answer
| Your project | Planning route | |---|---| | Roof PV up to 50 kW on a business building | Permitted development (Class J, microgeneration) | | Roof PV above 50 kW on a business building | Permitted development, after the council's prior-approval decision on design and appearance, glare included | | Roof of a building in a conservation area | Class J still applies to the roof; wall-mounted panels fronting a highway are excluded | | Listed building, or a building within its curtilage | Planning permission and listed building consent | | Scheduled monument | Not permitted development | | Ground-mounted array or solar carport | Outside Class J: confirm the route with the council |
The rest of this guide explains the limits behind each line.
What Class J is
Class J sits in Part 14 of Schedule 2 to the Town and Country Planning (General Permitted Development) (England) Order 2015. It covers solar on buildings that are not houses or blocks of flats: offices, warehouses, factories, shops, hotels, schools and farm buildings. Houses have their own rules under Class A, which is why advice written for homeowners, including our guide to solar panels in a conservation area, does not carry straight across to a business roof.
Class J has three parts. J(a) is solar thermal on a building. J(b) is microgeneration solar PV on a building, and microgeneration means up to 50 kW under the Energy Act 2004. J(c) is other solar PV on a roof, above 50 kW.
Systems up to 50 kW
A roof array up to 50 kW on a business building is permitted development provided it stays within the size limits. Nothing goes to the council first. The conditions that apply to every Class J system still hold: the panels are sited to keep their effect on the building's appearance and the area's amenity down, and they are removed when no longer needed.
In practice 50 kW is a large office roof, a retail unit or a small industrial unit.
Systems above 50 kW and prior approval
Above 50 kW, a roof system is still permitted development, but the council's prior-approval decision on design and external appearance, including glare, must be in place before work starts. Prior approval is not a planning application. The council looks only at those matters, not at whether solar should go on the roof at all.
The 1 MW cap that used to apply to roof systems was removed in December 2023, so a big distribution shed is no longer pushed into a full application on size alone.
Glare is one of the matters the council looks at, so it is worth showing how the panels face relative to nearby roads, railways and flight paths.
The size limits that apply to every roof
- On a pitched roof the panels may not stand more than 0.2 m proud of the roof slope.
- On a flat roof they may not rise more than 1 m above the highest part of the roof, chimneys excluded.
- Nothing may be within 1 m of the external edge of the roof.
- Class J does not apply to a listed building, a building within its curtilage, or a scheduled monument.
The 1 m edge rule is the one that most often changes a layout on a flat industrial roof. It costs some panels around the perimeter, but it also keeps a safe walkway for maintenance.
Conservation areas
Many Greater Manchester buildings sit in conservation areas, from city-centre streets to mill villages. For a business building, a conservation area does not take away Class J for the roof. What it does exclude is solar on a wall that fronts a highway. A roof system in a conservation area is treated like any other: under 50 kW is permitted development, above 50 kW needs the prior-approval decision.
Councils can narrow permitted development further with an Article 4 Direction. If your building is in a conservation area, ask the planning team whether a direction covers it before you commit.
Listed buildings
A listed building, or a building within its curtilage, needs planning permission and listed building consent for solar. Greater Manchester's mills, warehouses and Victorian commercial buildings include listed ones. Panels that cannot be seen from the street, such as on a rear roof slope, a valley between pitches or a flat roof behind a parapet, are the usual starting point for a consent application. A pre-application conversation with the borough's conservation officer saves time.
Ground-mounted arrays and carports
Class J covers equipment on a building. A ground-mounted array on spare land, or a solar carport over a staff car park, sits outside it. Some smaller schemes may fall under other permitted development classes, and larger ones need a planning application. The route depends on the site, so it is worth a call to the borough council before design work starts. Farms have their own considerations: our agricultural solar page covers barns and land-based systems.
The ten councils
Greater Manchester is ten boroughs, and each is its own local planning authority: Bolton, Bury, Manchester, Oldham, Rochdale, Salford, Stockport, Tameside, Trafford and Wigan. The national Class J rules are the same in all ten. What differs is where the conservation areas and Article 4 Directions are, and how long each council takes over a prior-approval request. A prior-approval request goes to the council for the borough where the building is, whether that is a unit in Trafford Park, a mill in Oldham or an office in Stockport.
Planning is only half of it: the grid
Planning decides whether the panels can go on the roof. The grid connection decides whether they can be switched on. Electricity North West is the distribution network operator for Greater Manchester. A system up to 16 A per phase, about 11 kW on a three-phase supply, is a G98 "connect and notify" job. Almost every commercial system is bigger, so it needs a G99 application and the network operator's approval before it is connected. Our guide to DNO applications and three-phase supplies explains the process.
Run planning and the G99 application side by side, not one after the other. The grid answer can change the system size, and with it the planning route.
Building regulations and the roof
Permitted development is about planning only. The roof still has to carry the extra load, so a structural check comes before design, and the electrical work has to meet the wiring regulations. The fire-safety code of practice for PV on roofs is RC62, from RISCAuthority and the Fire Protection Association; insurers set their own conditions on top of it. Planning the commercial solar panel maintenance regime at the design stage keeps the inspection record your insurer will ask for.
What to have ready
- The building's address and whether it is listed or in a conservation area (the council's map shows both).
- Roof drawings or a recent roof survey, and its age.
- Twelve months of half-hourly electricity data, which sets the system size.
- The supply capacity on your electricity bill or meter, for the grid application.
Next steps
If your project is a straightforward roof system, planning is unlikely to be the hard part. Size the system against your demand, check the roof, and get the G99 application moving early. For costs, see our commercial solar cost per kWp guide, and for the full service see commercial solar installation.