The Commercial Solar Installation Process, Step by Step

From enquiry to switch-on

We handle step 1 and match you with one MCS certified installer for the rest. The order can overlap: an installer often applies to the network operator while planning is being decided.

Survey and design

The survey decides whether the system can be built safely and what size makes sense. Under the MCS standard (MIS 3002):

• The roof structure. is checked by a competent person to make sure it can take the system's loads; a qualified structural engineer is consulted where the roof is unusual or there is any doubt.
• Weather tightness. The system must not affect the building's weather tightness or structural integrity for its life.
• Roof warranties. If the roof covering is under warranty, the warranty provider should be consulted first.
• Risk assessments. Suitable and sufficient risk assessments are done before work on site starts.

The design then sizes the system to your daytime use, from a year of half-hourly data. What the visit covers in detail: the commercial solar site survey.

Permissions and grid approval

Planning. Rooftop solar on a business building is often permitted development. In England, systems over 50 kW need the council's prior approval first; work can start when the council says approval isn't needed, grants it, or 56 days pass without a decision (Class J, J.4). Listed buildings always need consent. See planning permission and listed buildings.

The grid. Systems up to 16 A per phase connect under G98 and the installer notifies the network operator; larger systems connect under G99, which normally means applying before installation (ENA). The operator may agree, ask for changes, or set an export limit. This is often the longest wait. See grid connection for business solar.

Your landlord. If you rent, get written consent before you commit. See solar on a leased building.

Your duties as a commercial client

The Construction (Design and Management) Regulations 2015 apply to solar installations. HSE says a commercial client is any individual or organisation that carries out a construction project as part of a business, and client duties apply to them in full (HSE). For every project, a commercial client must:

• Arrange the project properly. Make suitable arrangements for managing it, including appointing the other dutyholders and allowing enough time and resources.
• Share information. Provide the information the designers and contractors need, such as asbestos surveys, drawings and site rules.
• Check the others do their part. Make sure the principal designer and principal contractor carry out their duties, and that welfare facilities are provided.
• Notify larger projects. Notify HSE where the work will last longer than 30 working days and involve more than 20 workers at any one time, or exceed 500 individual worker days.

A good installer will walk you through this and do most of the paperwork, but the duties stay with the business (HSE summary). On older roofs, ask about asbestos before anyone goes up: solar on an asbestos cement roof.

Installation days and disruption

• Access and edge protection. Scaffolding or edge protection goes up first; plan where it stands, where deliveries land and which entrances stay open.
• Roof work. Mounting, panels and cabling happen on the roof, mostly out of the way of day-to-day work.
• Inside the building. Inverters, isolators and cable runs to the distribution board; agree the routes and where the kit lives.
• The connection. Connecting to your electrics needs a short shutdown of the circuits affected. Ask for it to be scheduled outside your busiest hours.
• People and vehicles. Keep staff, customers and vehicles clear of the work areas; agree no-go zones in the plan.

Testing, handover and paperwork

The MCS standard covers systems up to a DC output of 50 kWp. It requires the system to be commissioned to a documented procedure and inspected and tested, and its model handover document includes (MIS 3002):

• A verification certificate. Signed by the people responsible for design, installation and testing, with the key components, rated power (kW DC) and estimated system performance.
• Test and inspection reports. For the electrical installation and the PV array.
• The next inspection. When the next inspection is recommended.
• Building regulations. Notification completed before handover, where the installer is responsible for it.

MCS says certification is a requirement for many UK government incentives (MCS), such as getting paid for exports under the Smart Export Guarantee. After switch-on: maintenance and insurance.