Solar Panel Electrical Requirements: What You Need to Know Before Installation

Installing solar panels is one of the smartest investments a homeowner in East Sussex can make. Energy bills continue to rise, and a well-designed solar PV system can dramatically reduce your dependence on grid electricity. However, before any panels go on your roof, there are important solar panel electrical requirements that must be met. Understanding these requirements upfront prevents delays, ensures your system is safe and compliant, and means you can start generating clean energy as quickly as possible.

In this guide, we cover every electrical aspect of a solar PV installation: from your consumer unit and inverter placement through to G99 grid connection applications, export tariffs, battery storage, and MCS certification. Whether you are in Eastbourne, Brighton, Hastings, or anywhere across East Sussex, this is your complete reference for getting solar right from the start.

Solar PV System Basics

Before diving into the electrical requirements, it helps to understand how a domestic solar PV system works. Each component plays a specific role, and the electrical infrastructure of your home must support them all.

Solar Panels

The panels themselves are mounted on your roof, typically south-facing for maximum generation. Each panel contains photovoltaic cells that convert sunlight into direct current (DC) electricity. A typical domestic installation in East Sussex uses between 10 and 16 panels, producing a system rated at 4kW to 6kW. Panel technology has improved significantly in recent years, and modern panels generate useful electricity even on overcast days, which is reassuring given the British climate.

Inverter

Solar panels produce DC electricity, but your home runs on alternating current (AC). The inverter is the critical bridge between the two. It converts the DC output from your panels into AC electricity that your home can use. Inverters are typically wall-mounted in a garage, utility room, or loft space. The inverter must be appropriately rated for your panel array and is one of the key components your electrician will specify during the design phase.

There are two main types of inverter used in domestic installations:

• String inverters -- A single unit that handles the entire panel array. Cost-effective and reliable, but the whole system's output is limited by the weakest-performing panel.
• Microinverters -- Small inverters fitted to each individual panel. More expensive, but each panel operates independently, which is advantageous if you have shading issues or panels on multiple roof aspects.

Generation Meter

A generation meter records exactly how much electricity your solar panels produce. This data is important for monitoring system performance and, if you are enrolled in an export tariff, for calculating payments for the surplus energy you send back to the grid. Some modern inverters include built-in monitoring, but a dedicated generation meter provides the verified data that energy companies require.

Grid Connection

Your solar PV system connects to the national electricity grid through your home's existing supply. This connection allows you to export surplus electricity when your panels generate more than you are using, and to draw from the grid when they are not generating enough. The grid connection is subject to specific regulations, most notably G99, which we cover in detail below.

Electrical Requirements for Solar Panel Installation

This is where many homeowners are surprised by the scope of work involved. A solar panel installation is not simply a matter of putting panels on a roof and plugging them in. Your home's electrical infrastructure must meet several specific requirements.

Consumer Unit Capacity

Your consumer unit (fuse box) needs a dedicated circuit for the solar PV system. This means you need at least one spare way in your consumer unit. If your current unit is full, or if it is an older model without RCD protection, a consumer unit upgrade will be required before the solar installation can proceed. This is one of the most common additional requirements we encounter, particularly in older properties across East Sussex.

The solar circuit must be protected by an appropriate MCB (Miniature Circuit Breaker) or RCBO (Residual Current Breaker with Overcurrent Protection). The rating depends on the inverter specification but is typically a 16A Type B MCB for systems up to 4kW. The circuit must also have RCD protection, which is standard on all modern consumer units.

Inverter Placement and Wiring

The inverter needs to be installed in a suitable location that meets several criteria:

• Ventilation -- Inverters generate heat during operation and need adequate airflow. Enclosed cupboards without ventilation are not suitable.
• Accessibility -- The inverter must be accessible for maintenance, monitoring, and isolation in an emergency.
• Cable run distance -- The DC cables from the roof panels to the inverter should be as short as practical to minimise energy losses. This typically means the inverter is located in the loft, on an upper floor wall, or in a garage directly below the panels.
• Proximity to consumer unit -- The AC output from the inverter connects to your consumer unit, so a reasonable cable run between the two is needed.

The DC wiring from the panels to the inverter uses specialised solar-grade cable rated for outdoor use and UV resistance. These cables are routed through the roof structure and down to the inverter location. All DC wiring must be clearly labelled as a safety precaution, since these cables are live whenever daylight falls on the panels and cannot be isolated at the consumer unit.

AC Isolator

An AC isolator switch must be installed between the inverter and the consumer unit. This allows the solar system to be disconnected from the household supply for maintenance or in an emergency. The AC isolator is typically a double-pole switch mounted adjacent to the consumer unit.

In addition, a DC isolator is fitted at the inverter to allow the DC supply from the panels to be disconnected. Some inverters have an integrated DC isolator, while others require a separate external unit.

Earthing

Proper earthing of the solar PV system is essential for safety. The metal frames of the solar panels, the mounting rails, and the inverter must all be properly earthed and bonded to your home's main earthing system. This protects against electric shock from fault currents and provides a safe path for lightning-induced surges.

The earthing requirements depend on your property's existing earthing arrangement (TN-C-S, TN-S, or TT). Your electrician will assess this during the site survey and design the earthing accordingly. Properties with a TT earthing system (common in rural parts of East Sussex) may require additional earth electrodes.

Main Supply Assessment

Your incoming electricity supply must be adequate to handle both the solar system and your normal household load. Most domestic properties have a 100A main fuse, which is sufficient for a standard solar installation. However, if your property already has high electrical demands (electric heating, EV charger, electric shower), your electrician will calculate the total demand to ensure the main supply is not at risk of being overloaded.

In some cases, particularly with larger solar systems combined with battery storage and EV charging, a main fuse upgrade may be required. This is arranged through your Distribution Network Operator (DNO) and is typically free of charge, though it can add time to the project.

G99 Grid Connection

One of the most important solar panel electrical requirements is compliance with the G99 engineering standard for connecting generation equipment to the distribution network. This is the formal process that governs how your solar PV system connects to the national grid.

What is G99?

G99 (formerly G83 for smaller systems) is the UK standard that sets out the technical requirements for connecting generating equipment, including solar PV, to the electricity distribution network. It ensures that locally generated electricity does not compromise the safety or quality of the grid supply.

When You Need G99 Approval

The application requirements depend on the size of your solar PV system:

• Systems up to 3.68kW (single-phase) -- These can be connected under a simplified notification process. Your installer notifies the DNO after installation, and connection is permitted unless the DNO objects within 28 days. Most domestic systems fall into this category.
• Systems between 3.68kW and 50kW (single-phase) -- These require a formal G99 application to your DNO before installation begins. The DNO assesses whether the local network can accommodate the additional generation and may impose conditions or require network upgrades. Approval typically takes 4 to 8 weeks but can take longer if the local network is already heavily loaded with generation.

For most East Sussex homes, a 4kW to 6kW system will require G99 application. This is not a reason to reduce your system size unnecessarily -- it simply means planning ahead.

The Application Process

As your installer, D J Fox Electrical handles the G99 application process on your behalf. Here is what it involves:

1. Site assessment -- We survey your property and design the system, determining the panel layout, inverter specification, and connection details.
2. Application submission -- We submit the G99 application to your DNO (UK Power Networks for East Sussex) with the system specifications, single-line diagram, and connection details.
3. DNO assessment -- UK Power Networks assesses whether the local network can accommodate your system. They check transformer capacity, voltage regulation, and existing generation on the circuit.
4. Approval or conditions -- The DNO either approves the connection, approves with conditions (such as export limiting), or in rare cases, requires network reinforcement before connection.
5. Installation -- Once approved, we install the system in accordance with the approved specification.
6. Commissioning notification -- After installation, we submit a commissioning confirmation to the DNO, completing the process.

Common G99 Issues

In coastal areas of East Sussex, particularly around Eastbourne and the surrounding towns, the electricity network can be relatively constrained. This means G99 applications sometimes face challenges:

• Network capacity -- In areas where many properties have already installed solar PV, the local transformer may be approaching its capacity for additional generation. This can result in export limiting conditions rather than outright refusal.
• Voltage rise -- Solar generation pushes voltage up on the local network. If the voltage is already high, the DNO may limit the size of your system or require an export limiter.
• Processing times -- During busy periods, DNO processing times can extend beyond the standard timeframes. We factor this into project planning and keep you informed throughout.

Export Tariffs: Getting Paid for Surplus Energy

One of the financial benefits of solar PV is the ability to earn money from the surplus electricity you export to the grid. The mechanism for this in the UK is the Smart Export Guarantee (SEG).

What is the Smart Export Guarantee?

The Smart Export Guarantee is a government-backed scheme that requires licensed electricity suppliers with more than 150,000 customers to offer a tariff for exported electricity from small-scale generation such as solar PV. The supplier must offer a rate greater than zero, though the actual rate varies between suppliers and is commercially determined.

Current SEG Rates

As of 2026, typical SEG export rates range from 4p to 15p per kWh, depending on the supplier and the tariff structure. Some suppliers offer fixed rates, while others offer variable rates that track wholesale electricity prices. The best rates tend to be offered by suppliers who also provide your import electricity, as a bundled arrangement.

To put this in perspective, a typical 4kW solar PV system in East Sussex generates approximately 3,400 to 3,800 kWh per year. If you export around 50 percent of this (a reasonable estimate for a household that is out during the day), that is approximately 1,700 to 1,900 kWh of exports. At 10p per kWh, this equates to 170 to 190 pounds per year in export payments, on top of the savings from the electricity you use directly.

SEG Requirements

To qualify for SEG payments, you must meet several requirements:

• Your installation must be MCS certified (see below)
• You must have a smart meter capable of recording export data (or a dedicated export meter)
• Your system must be no larger than 5MW (easily met by domestic installations)
• You must apply to an SEG licensee -- your installer does not arrange this; you apply directly to your chosen supplier

Maximising Your Returns

The key to maximising financial returns from solar PV is to use as much of your generated electricity as possible, rather than exporting it. Electricity you use directly saves you the full import rate (currently 24-28p per kWh), whereas exported electricity earns you only the SEG rate (4-15p per kWh). Strategies to increase self-consumption include:

• Running high-demand appliances (washing machine, dishwasher, tumble dryer) during peak generation hours
• Heating water with an immersion heater diverter during the day
• Installing battery storage to capture surplus generation for use in the evening
• Charging your electric vehicle during daylight hours

Battery Storage Considerations

Adding battery storage to a solar PV system is increasingly popular and makes excellent financial sense. A battery allows you to store surplus solar electricity generated during the day and use it in the evening when your panels are no longer producing. However, battery storage introduces additional electrical requirements.

Electrical Modifications for Battery Storage

A battery storage installation requires the following electrical considerations:

• Additional circuit -- The battery system needs its own dedicated circuit from the consumer unit, separate from the solar PV circuit. This means another spare way is needed in your consumer unit.
• Hybrid inverter or additional inverter -- If you are installing battery storage alongside solar PV, a hybrid inverter that manages both solar generation and battery charging is the most efficient option. Retrofitting a battery to an existing solar system may require an additional battery inverter.
• Increased cable capacity -- The combined current from solar generation and battery discharge can exceed the capacity of the original solar circuit. Your electrician must calculate the maximum demand and size the wiring accordingly.
• Emergency power supply (EPS) -- Some battery systems can provide backup power during a grid outage. If you want this feature, additional wiring and a changeover switch are required to isolate critical circuits from the grid while the battery supplies them.

Battery Capacity and Sizing

Battery capacity is measured in kilowatt-hours (kWh) and should be matched to your solar generation and evening consumption:

• 5kWh battery -- Suitable for smaller households or systems up to 3kW. Stores enough for a typical evening's electricity use.
• 10kWh battery -- The most popular choice for a 4kW to 6kW solar system. Stores enough to cover evening and early morning use for most households.
• 13-15kWh battery -- For larger households with higher consumption or those wanting maximum self-sufficiency.

The most common domestic batteries include the Tesla Powerwall (13.5kWh), GivEnergy (5-9.5kWh modules), and the Fox ESS range. All require professional installation by a qualified electrician.

Location and Environmental Requirements

Batteries must be installed in a location that meets the manufacturer's specifications for temperature range, ventilation, and access. Most lithium-ion batteries can be wall-mounted in a garage, utility room, or exterior wall, but they must be protected from extreme temperatures. In East Sussex, outdoor-rated batteries should be shielded from direct salt spray in coastal areas.

MCS Certification

The Microgeneration Certification Scheme (MCS) is a quality assurance standard that is effectively mandatory for any domestic solar PV installation in the UK. Understanding why it matters will save you significant problems down the line.

What is MCS?

MCS is an industry-led quality assurance scheme supported by the UK government. It certifies both the products (solar panels, inverters, batteries) and the installers who fit them. An MCS-certified installation means that the products meet tested performance standards and that the installation has been carried out by a qualified, audited installer following approved procedures.

Why MCS Certification is Essential

MCS certification is not legally required to install solar panels, but without it you are locked out of almost every financial benefit:

• Smart Export Guarantee -- You cannot receive SEG payments without MCS certification
• VAT relief -- The current zero percent VAT rate on domestic solar installations applies only to MCS-certified installations
• Government grants -- Any future grant schemes are virtually certain to require MCS certification
• Property value -- Prospective buyers and their surveyors will look for MCS certification as evidence of a quality installation
• Warranty protection -- Most solar panel and inverter manufacturers require MCS-certified installation for their product warranties to be valid

What MCS Certification Involves

When D J Fox Electrical carries out your solar panel installation, the MCS certification process includes:

• System design to MCS standards, including shading analysis and performance estimation
• Installation using MCS-certified products
• Commissioning and testing to MCS procedures
• Registration of your system on the MCS database
• Issue of an MCS certificate for your records
• Handover documentation including performance estimates and maintenance guidance

Cost Breakdown

Understanding the full cost of a solar PV installation helps you plan your investment and calculate the payback period.

Typical Costs in East Sussex (2026)

These prices include panels, inverter, mounting system, all electrical work, MCS certification, and G99 application. VAT is currently zero percent on domestic solar installations.

Additional Costs to Consider

Payback Period

The payback period for a solar PV system in East Sussex depends on several factors, but typical figures for a 4kW system are:

• Annual generation: 3,400 to 3,800 kWh
• Electricity savings (50 percent self-consumption at 27p/kWh): 460 to 515 pounds per year
• Export income (50 percent at 10p/kWh): 170 to 190 pounds per year
• Total annual benefit: 630 to 705 pounds per year
• Payback period on a 6,000 pound system: 8.5 to 9.5 years

After the payback period, your solar panels continue generating free electricity for another 15 to 20 years. Most modern panels carry a 25-year performance warranty.

Adding battery storage extends the payback period slightly but increases self-consumption from around 50 percent to 70-80 percent, significantly reducing your reliance on grid electricity and protecting you against future energy price increases.

Local Considerations for East Sussex

Installing solar panels in coastal East Sussex comes with specific considerations that an experienced local electrician will account for during the design and installation.

Salt Air and Coastal Corrosion

Properties in and around Eastbourne, Brighton, Hastings, Seaford, and other coastal towns are exposed to salt-laden air, which accelerates corrosion of metal components. For solar installations, this affects:

• Mounting systems -- Marine-grade stainless steel or aluminium fixings are essential. Standard zinc-plated fixings will corrode within a few years in a coastal environment.
• Electrical connections -- All external junction boxes and connectors must be rated for coastal conditions. We use IP65-rated enclosures and corrosion-resistant connectors as standard on coastal installations.
• Inverter location -- Where possible, the inverter should be installed indoors or in a well-ventilated but sheltered location, away from direct exposure to salt spray.
• Maintenance schedule -- Coastal installations benefit from more frequent visual inspection, particularly checking mounting fixings and external cable connections for signs of corrosion.

Wind Loading

East Sussex is exposed to strong south-westerly winds, particularly along the coast and on the South Downs. The mounting system must be designed to withstand the wind loads specified in the structural assessment. This is particularly important for properties on exposed hillsides or clifftop locations. In some cases, the structural assessment may require additional fixings or a lower-profile mounting arrangement.

Roof Orientation and Shading

The South Downs and the coastal topography of East Sussex mean that many properties do not have perfectly south-facing roofs. This is not a significant problem. East-facing or west-facing panels still generate around 85 percent of the output of south-facing panels, and a split east-west array can actually provide a more even generation profile throughout the day. During the site survey, we use shading analysis tools to model your specific roof and predict annual generation accurately.

Planning Permission

Most domestic solar installations in East Sussex do not require planning permission, falling under permitted development rights. However, there are exceptions:

• Listed buildings -- Solar panels on a listed building require listed building consent from the local planning authority (Eastbourne Borough Council, Lewes District Council, or the relevant authority)
• Conservation areas -- Panels that face a highway in a conservation area may require planning permission
• South Downs National Park -- Properties within the National Park may face additional restrictions. Many parts of the area around Eastbourne, Lewes, and the surrounding villages fall within the Park boundary
• Flats -- Installing panels on a flat or maisonette may require freeholder consent and possibly planning permission

We advise on planning requirements during the initial site survey and can assist with any applications if needed.

Choosing a Qualified Solar Electrician

Solar PV installation is specialist electrical work that requires specific qualifications and certifications beyond standard domestic electrical competence.

Qualifications to Look For

When choosing a solar PV electrician in Eastbourne or anywhere in East Sussex, verify the following:

• NICEIC Approved Contractor (or equivalent competent person scheme) -- confirms competence for all electrical work
• Part P Registration -- legal requirement for domestic electrical installations
• MCS Certification -- essential for SEG eligibility, VAT relief, and warranty compliance
• City and Guilds 2399 (or equivalent) -- the specific qualification for solar PV installation
• BS 7671 (18th Edition) -- current wiring regulations certification
• Public liability insurance -- minimum 2 million pounds cover

Why Local Knowledge Matters

A local electrician who regularly works in your area understands the specific challenges of East Sussex properties: coastal corrosion, South Downs National Park planning restrictions, local DNO (UK Power Networks) processes, and the structural characteristics of regional building styles. This experience translates directly into a smoother installation and fewer unexpected complications.

Our Coverage Area

D J Fox Electrical provides professional solar panel installation across East Sussex, including:

• Eastbourne -- all areas including Old Town, Meads, Upperton, Langney, Sovereign Harbour, and Hampden Park
• Brighton and Hove -- Kemp Town, Rottingdean, Saltdean, Patcham, Woodingdean, and all surrounding areas
• Hastings and Bexhill -- St Leonards, Battle, and surrounding villages
• Lewes -- including Ringmer, Barcombe, and Ditchling
• Hailsham -- Polegate, Stone Cross, Hellingly, and Heathfield
• Seaford -- Newhaven, Peacehaven, and Telscombe Cliffs

Frequently Asked Questions

Do I need to upgrade my consumer unit for solar panels?

Not always, but it is common. Your consumer unit needs a spare way for the solar circuit and must have RCD protection. If your current unit is full or outdated, a consumer unit upgrade will be required. We assess this during the free site survey and include any upgrade costs in your quotation.

How long does a solar panel installation take?

A typical domestic installation takes 2 to 3 days. This includes scaffolding erection, panel mounting, inverter installation, electrical connection, and testing. The G99 application should be submitted several weeks before the installation date to avoid delays.

Can I install solar panels on a north-facing roof?

North-facing panels generate significantly less electricity than south, east, or west-facing panels and are generally not recommended for primary arrays. However, if you have no alternative roof aspect, modern high-efficiency panels can still produce a worthwhile output. We will model the expected generation during the site survey and give you an honest assessment of whether the investment is justified.

What happens during a power cut if I have solar panels?

Without battery storage, your solar PV system will automatically shut down during a grid power cut. This is a safety requirement to prevent your system from feeding electricity into the grid while engineers are working on it. If you want backup power during outages, a battery system with an Emergency Power Supply (EPS) function provides this capability.

Do solar panels work in winter?

Yes. Solar panels generate electricity from daylight, not direct sunshine. In East Sussex, a typical system produces around 25 percent of its annual output during the winter months (October to March) and 75 percent during the summer months. Generation on a bright winter day can be surprisingly good, and modern panels perform well in overcast conditions.

Will solar panels damage my roof?

A properly installed solar PV system should not damage your roof. The mounting brackets are fixed to the roof rafters (not just the tiles) and are weatherproofed with flashing or sealant. The panels actually protect the area of roof beneath them from weather exposure. Your installer should carry out a structural assessment before installation to confirm that your roof can support the additional load.

Ready to Explore Solar for Your Home?

Solar PV is a proven technology that pays for itself and then generates free electricity for decades. The electrical requirements may seem complex, but that is exactly what a qualified solar PV electrician is here to manage. From assessing your consumer unit and designing the system through to handling the G99 application and commissioning the installation, every technical detail is taken care of.

D J Fox Electrical is an NICEIC Approved, Part P Registered, and MCS-certified solar installer serving Eastbourne, Brighton, Hastings, and the whole of East Sussex. We provide honest advice, transparent pricing, and professional installation backed by comprehensive warranties.

Book your free solar assessment today. Call us on [PLACEHOLDER] or email info@djfoxelectrical.com. We will visit your property, assess your roof, review your electricity usage, and provide a detailed quotation with realistic generation and savings estimates. There is no obligation, and the survey is completely free.