How Are Solar Panels Installed?

Author: Steve Fairless
Originally Published: 11th December 2023 · Updated: 3rd September 2026

Stage 1: understand the property and electricity demand

Before we specify equipment, we need to understand what the customer is trying to achieve. Annual electricity consumption, daytime demand, future EV or heat-pump plans, battery objectives and export preferences all influence the design. A system built only around the maximum roof area can be financially and technically different from one designed around the property's load profile.

For a domestic solar PV system for a home project, the initial information usually includes recent electricity usage, roof type, orientation, access, shading and the proposed inverter/battery location. Commercial projects can require half-hourly consumption data and more detailed electrical information.

Stage 2: carry out the site and roof survey

The survey checks roof condition, structure, dimensions, usable areas, obstructions, shading, cable routes and the existing electrical installation. The current MCS MIS 3002 standard requires the roof structure to be assessed for suitability and unusual structures or areas of doubt can require a suitably qualified structural engineer.

Weather-tightness matters just as much as load. Mounting should not create an avoidable leak path, and the roof warranty position should be considered before work starts. MCS also requires installers to consult the roof warranty provider where applicable and tell the customer in writing if the proposed work may invalidate that warranty.

Stage 3: design the array and estimate performance

The survey information is turned into a proposed module layout, inverter specification and annual-generation estimate. MCS requires written technical information including the module and inverter datasheets, proposed module layout and a performance estimate. Where relevant, optimiser, microinverter or battery datasheets are also part of the pre-contract information.

Layout design considers more than fitting a target number of modules. Roof edges, ridges, gutters, shading, wind exposure and access all influence the final arrangement. For domestic roofs, MIS 3002 includes a 400 mm roof-edge consideration unless specific measures justify another design.

Stage 4: planning and DNO checks happen before the physical install where needed

Many ordinary domestic roof arrays in England are permitted development, but listed buildings, conservation restrictions, flat roofs and other circumstances can need additional planning attention. Separately, the electricity network connection route depends on the generating equipment.

Current ENA G98 covers micro-generators up to and including 16 A per phase. On a nominal 230 V single-phase supply, that corresponds to 3.68 kW of registered generation capacity. Systems outside the G98 conditions normally follow G99 or another applicable connection route, which can require approval before installation.

We treat the network route as a design input rather than an afterthought. A customer asking for a larger inverter or battery system may need a different DNO application, export limitation or equipment configuration.

Stage 5: safe access and scaffolding are prepared

Roof work is one of the highest-risk parts of the project. HSE states that all roof work is highly dangerous and that almost one in five deaths in construction involve roof work. Safe access, edge protection, fragile surfaces and competent workers therefore have to be planned before modules are carried onto the roof.

On typical sloping domestic roofs, scaffolding and suitable edge protection are used to control fall risk. Fragile roofs need additional precautions. These controls are not cosmetic extras; they are part of completing the installation safely.

Stage 6: install the roof anchors and mounting rails

On a typical tiled or slate pitched roof, the installer identifies structural fixing points, lifts or removes the necessary roof covering and fixes mounting hardware to the structural members. Rails are then aligned and secured. The roof covering is reinstated around the brackets in a way that maintains weather resistance.

MCS specifically addresses tile and slate interfaces: roof coverings may need appropriate notching or flashing so that mounting hardware does not create pressure points or prevent correct seating. The exact method depends on the roof covering and mounting system.

Stage 7: mount and electrically connect the PV modules

The modules are lifted into position, aligned and clamped to the mounting system in accordance with the product instructions. DC cables are routed and secured to avoid abrasion, unsupported loops, sharp edges and exposure that could cause premature deterioration.

Modules may be wired in strings to a central or hybrid inverter, or connected to panel-level electronics such as microinverters or optimisers where the chosen architecture uses them. Polarity, connectors and cable management are critical because faults on the DC side can be difficult to interrupt once the array is generating.

Stage 8: install the inverter and, if specified, battery storage

The inverter converts DC electricity from the array into AC electricity suitable for the property and grid. It needs a location that meets the manufacturer's environmental, access and ventilation requirements. Cable length, route and serviceability also matter.

Where a solar battery is included, its installation is a separate engineering task. Battery siting, fire safety, electrical protection, communications and operating temperatures must be considered. The battery should not simply be placed wherever spare wall space happens to exist.

Stage 9: connect the AC side to the property

A competent electrician connects the inverter output into the property's electrical installation using appropriate protective devices and isolation. The design must coordinate with the consumer unit, earthing arrangement and existing protective measures. Labelling and isolators allow future engineers or emergency personnel to identify the PV circuits.

If upgrades are needed to the consumer unit, earthing or supply arrangement, those should be identified early so they do not become a surprise during commissioning.

Stage 10: test and commission the complete system

Before handover, the installation is tested to confirm that the DC and AC circuits are safe and correctly configured. Depending on the system, tests and checks can include polarity, insulation resistance, protective devices, inverter settings, generation, communications and monitoring.

The engineer then commissions the inverter and any battery, verifies that monitoring is reporting correctly and confirms that the system behaves as designed. A successful app login is not a substitute for electrical testing.

Stage 11: complete the DNO registration or approval process

For a straightforward single-premises G98 installation, the “connect and notify” route can allow installation first, followed by notification to the DNO within 28 days. The GOV.UK energy-device registration guidance and DNO procedures set out this requirement. Larger or more complex G99 systems generally require the relevant application/approval route before connection.

The paperwork should match what has actually been installed: inverter model, registered capacity, export-limitation equipment where applicable and commissioning information. This is one reason changing equipment at the last minute without checking the network application can cause problems.

Stage 12: MCS certification and customer handover

The customer should receive the documentation needed to understand and operate the system. That can include system layout, component information, warranties, electrical certificates, MCS certificate, DNO information, monitoring instructions and shutdown/isolation guidance.

We also explain what normal generation looks like, how to spot faults and when to contact us. A good handover turns a completed installation into a system the owner can actually manage.

How long does installation take?

The physical roof and electrical work on a straightforward domestic system can be relatively quick, but the overall project duration can be much longer because design, scaffold scheduling, equipment availability, DNO approval and any planning or structural work occur around the installation days. A G99 application or network upgrade can be the critical path on a larger project.

That is why a professional quotation should distinguish the expected installation duration from the total project programme.

What makes one solar installation better than another?

Component quality matters, but installation quality determines whether those components operate in the conditions they were designed for. Roof integrity, cable management, inverter location, protection settings and documentation all affect long-term performance.

What happens after installation?

Solar is low-maintenance but it should still be monitored. Unexpected generation drops, inverter warnings, physical damage or electrical faults need investigation. Our solar servicing work covers inspections, diagnostics and remedial support for both systems we installed and suitable systems installed by others.

Customers who are still at the planning stage can request a solar quote. We start with energy usage and property information so the proposal reflects the system that can be installed safely and the output it is reasonably expected to produce.

The installation process in one sentence

Solar panels are installed by surveying and designing the system first, creating safe roof access, fixing a weather-tight mounting system, installing and wiring the modules, integrating the inverter/battery and AC protection, testing the system, completing the correct network and certification paperwork, and handing over a documented installation to the customer.