Survey First, Panels Second: Preparing a UK Property’s Electrics for Solar and Storage

Solar panels and battery storage have moved from niche addition to mainstream consideration for many UK homes and managed properties. Yet the conversation often begins with panel counts, roof orientation and payback periods, while the electrical installation that must support the system is treated as a detail to resolve later. That order is worth reversing. A proper survey before installation is not a delay; it is the most reliable way to prevent expensive rework and to ensure the finished system can be maintained safely for years.

The installation is a system, not an accessory

An inverter, battery and array of panels do not sit apart from the existing wiring. They become part of the property’s electrical installation, and they introduce a source of supply that the consumer unit, earthing arrangement and isolation strategy must accommodate. Where the existing installation is older, poorly documented or already near its capacity, adding generation without a clear assessment can create nuisance tripping, awkward maintenance access and a handover pack that satisfies nobody.

The purpose of a pre-installation electrical survey is therefore straightforward: to establish what is already there, what can safely be added, and what must be improved first. It should be carried out by a competent electrician working alongside the solar designer, not after the scaffold has gone up.

Consumer unit capacity and circuit allocation

The consumer unit is the first practical checkpoint. Spare ways are only part of the question. The busbar rating, the arrangement of RCDs and RCBOs, the presence of surge protection and the physical space for additional cabling all matter. A board that appears to have two spare ways may still be unsuitable if the shared RCD protection is already prone to nuisance tripping or if the inverter and battery would be grouped onto the same residual current device.

Dedicated circuits for the inverter and, where applicable, the battery connection should be planned rather than squeezed in. Labelling at the origin is equally important: a future contractor or emergency responder should be able to identify the presence of a second source of supply without tracing cables. Where the existing unit is outdated, replacement before installation is usually more economical than a series of adaptations afterwards.

Siting the inverter and battery

The location of the inverter and battery is often decided by convenience rather than by the manufacturer’s instructions. Both need appropriate ventilation, protection from extremes of temperature and moisture, and enough clear space for isolation and fault-finding. Lofts and cupboards can be workable in some cases, but not by default. Battery storage in particular requires careful thought about fire separation, escape routes and the specific installation requirements of the chosen product.

Access is not a minor consideration. An inverter mounted high on a wall or behind stored items may be safe on the day of commissioning but difficult to isolate in an emergency. The survey should agree a location that satisfies the manufacturer, the building’s construction and the practical needs of maintenance.

Earthing and bonding

Earthing is the area most often assumed rather than verified. The property’s earthing arrangement, whether TN-S, TN-C-S or TT, affects what the inverter requires and how the system should be configured. Some equipment has specific requirements; a TT installation may need an additional earth electrode, and the connection must be tested rather than presumed.

Bonding of array frames and mounting rails should follow the manufacturer’s instructions and BS 7671. It is not enough to assume that a metal roof or rail is inherently earthed through its fixings. The survey should record the existing main protective bonding of services and identify any bonding that the new installation will require.

Isolation and safe maintenance

A solar installation has more than one point of isolation, and each should be clear, accessible and labelled. The DC side, the AC side and the battery connection all need a considered switching strategy. Where the inverter is remote from the consumer unit, the labels at the origin should make the relationship obvious.

Good practice also means thinking about the future electrician who will attend a fault. A schematic diagram inside the handover pack, durable labels at the equipment and a lockable isolation point are small measures that make maintenance safer. They cost little at installation and are difficult to retrofit neatly.

DNO notification and export limits

Any grid-connected generation must be notified to the Distribution Network Operator before it is connected. Small-scale domestic systems generally fall under the G98 process, while larger or multiple installations may require a G99 application. The DNO may impose an export limitation, and that limit must be configured and documented rather than assumed.

Export limitation settings belong in the handover record. If a future battery or second array is added, the original approval and settings should be reviewed. Connecting generation without the correct notification is not a paperwork formality; it can affect network safety and may breach the distribution code.

Records for the next owner

A solar installation should leave behind a coherent record. That includes the Electrical Installation Certificate for the new work, building regulations compliance where applicable, the MCS certificate if the system was installed under a certified scheme, product datasheets, warranty details, DNO approval, export limitation settings and a single-line schematic. Future buyers, insurers and maintenance contractors will ask for these documents, and an EICR in later years will be easier to produce if the original record is complete.

A pre-installation survey checklist

Before work begins, confirm the condition and capacity of the consumer unit, the earthing arrangement, the proposed cable routes, the inverter and battery locations, the isolation strategy, the DNO notification status and the export limitation. Agree who is responsible for each item and record the decisions. That short list prevents most of the surprises that turn a straightforward installation into a series of unplanned alterations.

Solar and storage can be a sound investment for a UK property, but only when the electrical groundwork is treated with the same care as the panels on the roof. A survey-led approach keeps the installation safe, supports compliance and leaves the next person with a system they can understand.