Solar Panel Installation

What solar panel installation actually involves

A solar installation is three trades in sequence: scaffolding, roof work and electrical work. Most of what separates a good installation from a poor one happens where those three meet — how fixings are set into the roof structure, how the roof is weathered afterwards, and how the DC and AC sides are routed, isolated and labelled.

We survey every property before quoting. Not because it is a sales step, but because the things that determine the price and the design — rafter spacing, covering condition, the state of the consumer unit, where a scaffold can stand — cannot be seen from an aerial photograph.

Designing the system

Sizing starts with your consumption, not your roof. A large array on a house that uses very little during the day exports most of what it makes, and export is worth considerably less than the electricity you avoid buying. So the first question is how much you use and when.

From there the design covers:

• Array layout. Panel positions set out against the actual rafter centres, keeping clear of ridges, hips, verges and vents.
• Orientation and pitch. South gives the highest annual total. East and west split arrays produce less in total but spread it across the morning and evening, which frequently suits a household better — particularly with storage.
• Shading. Chimneys, trees, dormers and neighbouring buildings, assessed across the year rather than on the day. Where shading is unavoidable, optimisers or a separate string limit the damage.
• Inverter selection. Sized to the array, chosen for the shading situation, and specified as a hybrid where a battery is planned now or later.

The roof

The roof covering determines the fixing method. Concrete and clay tiles take a tile hook set into the rafter with the tile relieved so it sits back down flat. Slate needs a different approach and more care, because slate is brittle and an unsympathetic fixing cracks it. Interlocking tiles are the easiest; plain clay tiles are the fiddliest.

Whatever the covering, fixings go into rafters. Not into battens, not into whatever is convenient. This is the single most common failing we find when we inspect other people’s work.

The electrical side

The array feeds DC to the inverter, which converts it to AC for the house. Around that sit the parts that make it safe and serviceable: DC isolation at the array and at the inverter, AC isolation, over-current protection, a generation meter, and labelling that tells the next electrician what they are looking at.

We assess the consumer unit at survey. On older properties it is common to find a board that is serviceable but full, or one that is due replacement anyway. We would rather price that into a fixed quotation than raise it as a variation on the day.

Notification and certification

Domestic systems are notified to the Distribution Network Operator. Where total generation capacity is 16A or less per phase — roughly 3.68kW on a normal single-phase supply — that is a G98 notification made within 28 days of commissioning. Above that threshold it is a G99 application, which must be approved before installation. That approval takes time, and it is one of the reasons a larger system needs planning further ahead.

The installation is certified under MCS, which matters for more than paperwork: you need it to apply for a Smart Export Guarantee tariff.

What you get at handover

Every installation is commissioned and tested before we leave, and you get a documentation pack: MCS certificate, Electrical Installation Certificate, DNO paperwork, manufacturer warranties registered in your name, the system design, and the monitoring set up on your phone with someone showing you how to read it.