Commercial Solar Panels in East Sussex

Our normal design envelope is based around up to approximately 50 kW of inverter capacity (AC). That is the limit of the inverter’s AC output — not necessarily the size of the panel array on the roof.

• Solar panels are rated in DC kilowatt-peak (kWp) — the maximum DC power the array could produce in ideal conditions.
• Commercial roofs generally take larger-format, higher-wattage panels than the 450–500W modules we fit on homes, so the array reaches its kWp with fewer panels.
• The inverter converts that DC power to AC for your building and is rated in kilowatts (kW) AC.
• A well-engineered system can connect a DC array larger than the inverter’s AC rating where the design, export limits, and DNO connection allow — the inverter clips peak output rather than wasting the roof space.
• Projects needing inverter capacity well above 50 kW AC usually involve a substantially more involved grid-connection process. That is not the commercial market we primarily target.

Steel portal frame units, flat roofs and pitched tile roofs all take solar. What changes is the mounting, the weight and the survey. Before we design an array we check that the roof structure can carry the extra loading the panels and their mountings will impose, both the weight itself and the wind. Where the structure is unusual, or there is any doubt, a structural engineer is consulted. That check is what the MCS solar PV installation standard requires, and it happens before we quote a firm design. Our guide to solar for small businesses in East Sussex goes through each roof type in more detail, and it is linked at the foot of this page.

• Steel portal frame with profiled metal sheet. The standard modern industrial or agricultural unit. Panels clamp to the ribs of the sheet or bolt through to the purlins, and there is usually a large clear area with no chimneys or dormers in the way.
• Flat roof. Panels sit on frames that are either weighted down with ballast or fixed through the covering. Ballast adds weight, so the structural check matters most here. Where the roof covering is still under warranty, we speak to the warranty provider before anything is fixed through it.
• Pitched tile. The same method as a house, on a bigger roof. Access and edge protection are the main differences.
• Roof condition comes before roof type. We will not put panels on a covering that is near the end of its life, because taking an array off again to redo the roof costs more than doing the roof first.

We assess your existing supply, main distribution board, and spare capacity during survey. System layout, inverter selection, and cable routes are designed to suit three-phase installations where that is what the site requires.

• The connection rules are set in amps, not kilowatts. Engineering Recommendation G98 covers generation up to 16 A per phase.
• G98 states that 16 A per phase is 3.68 kW on a single phase supply and 11.04 kW on a three phase supply. So a three phase supply lets you fit about three times as much before the fuller G99 application applies.
• So a 10 kW inverter is a G99 job on a single phase supply, and can be a G98 job on three phase, provided everything that generates at the site, including any battery, stays within 16 A per phase in total. If your unit is single phase and you want a larger system, ask about a three phase supply early.

We handle the relevant DNO application and notification work as part of the project. The exact route depends on system size, export arrangements, and what your local network operator requires — we explain the steps in your proposal rather than promising a single outcome for every site.

Where export is constrained, we can design with export limitation or inverter controls so the system operates safely within what the connection allows. Surplus energy is then used on site first, which is often where the best savings come from on commercial tariffs anyway.

Batteries can shift solar energy into evening hours, support peak-shaving, or work with time-of-use tariffs. We recommend storage only where your usage pattern and economics justify it. Many commercial projects are designed without batteries.

Where available, half-hourly electricity data (from a smart meter or your supplier) helps us model when you actually use power through the day and week. That leads to a system sized around real consumption rather than simply filling the roof.

• Annual kWh totals are helpful, but interval data shows peak demand and overnight baseload.
• If you do not have half-hourly data yet, we can advise how to obtain it from your supplier or meter operator.
• The goal is a design that maximises on-site use of generated electricity.

A commercial business case typically considers self-consumed solar (avoided imported electricity), any exported electricity, equipment lifetime, maintenance, and payback over the expected system life. Exact figures depend on your tariff, usage, and system specification; we set these out in your written proposal.

• Self-consumption usually delivers the strongest savings on commercial electricity rates.
• Export income may contribute where surplus is sold under a Smart Export Guarantee or supplier export tariff.
• VAT treatment for non-domestic solar can differ from residential projects. We do not quote VAT rates on this page — your formal quote will reflect the VAT position applicable to your project.