{"id":3360,"date":"2026-06-12T07:33:52","date_gmt":"2026-06-12T07:33:52","guid":{"rendered":"https:\/\/mywarmhome.co.uk\/stage\/?page_id=3360"},"modified":"2026-10-12T06:41:54","modified_gmt":"2026-10-12T06:41:54","slug":"solar-in-depth","status":"publish","type":"page","link":"https:\/\/mywarmhome.co.uk\/stage\/solar-in-depth\/","title":{"rendered":"Solar in Depth"},"content":{"rendered":"\n
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SOLAR \/ TECHNICAL HOMEOWNER GUIDE<\/p>\n\n\n\n

Solar in depth.<\/h1>\n\n\n\n

Understand the technology, grid connection, system components, storage and the checks that matter after installation.<\/p>\n<\/div>\n<\/div><\/div>\n\n\n\n

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01<\/p>\n\n\n\n

Understand<\/h3>\n\n\n\n

Solar PV, solar thermal and main components.<\/p>\n<\/div>\n\n\n\n

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02<\/p>\n\n\n\n

Connect<\/h3>\n\n\n\n

DNO, G98\/G99, export and metering.<\/p>\n<\/div>\n\n\n\n

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03<\/p>\n\n\n\n

Inspect<\/h3>\n\n\n\n

Equipment, wiring, labels and handover.<\/p>\n<\/div>\n\n\n\n

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04<\/p>\n\n\n\n

Store & protect<\/h3>\n\n\n\n

Batteries, diverters and safe aftercare.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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THE SHORT VERSION<\/p>\n\n\n\n

There is more to solar than the panels.<\/h2>\n<\/div>\n\n\n\n
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Solar PV produces electricity; solar thermal collects heat for water. Both rely on matching the technology to the home, understanding the installation and keeping clear records.<\/p>\n\n\n\n

This is the technical companion to the first Solar homeowner guide. It covers the equipment behind the panels, grid-connection paperwork, safe installation details, export payments, batteries and diverters.<\/p>\n\n\n\n

Good solar performance involves roof suitability, product compatibility, electrical protection, access for maintenance, the electricity network and an informed homeowner. The installation should be understood as one complete system.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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01 \/ KNOW THE TECHNOLOGY<\/p>\n\n\n\n

Solar PV and solar thermal do different jobs.<\/h2>\n\n\n\n

They both use energy from sunlight, but produce different outputs. It is important to distinguish an electrical solar PV array from a solar thermal collector before comparing specifications.<\/p>\n\n\n\n

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01<\/p>\n\n\n\n

Solar PV<\/h3>\n\n\n\n

Photovoltaic cells, typically using silicon semiconductors, turn light into direct-current (DC) electricity.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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02<\/p>\n\n\n\n

Inverter<\/h3>\n\n\n\n

The inverter converts DC electricity to alternating-current (AC) electricity suitable for household circuits.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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03<\/p>\n\n\n\n

Solar thermal<\/h3>\n\n\n\n

Collectors absorb solar energy as heat to support a domestic hot-water system, using a purpose-designed circuit.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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04<\/p>\n\n\n\n

The complete system<\/h3>\n\n\n\n

Mounting, cabling, controls, protection, metering and ongoing maintenance all matter alongside the roof equipment.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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\"Illustration\n\t\t\t\n\t\t\t\t\n\t\t\t<\/svg>\n\t\t<\/button><\/figure>\n<\/div>\n\n\n\n
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Solar PV in a little more detail<\/h3>\n\n\n\n

PV cells absorb light, produce DC electricity and feed an inverter. The home uses available generation; depending on the design, any surplus may charge a battery or be exported.<\/p>\n\n\n\n

Solar thermal in a little more detail<\/h3>\n\n\n\n

Domestic systems commonly use flat-plate collectors or evacuated tubes to transfer collected heat into a hot-water store. Collector and system behaviour depends on seasonal conditions and suitable over-temperature protection.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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01 \/ RECOGNISE THE EQUIPMENT<\/p>\n\n\n\n

Panels, collectors and inverters.<\/h2>\n\n\n\n
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\"Solar
Inverter<\/figcaption><\/figure>\n<\/div>\n\n\n\n
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\"Solar
Solar PV<\/figcaption><\/figure>\n<\/div>\n\n\n\n
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\"Solar
Solar thermal<\/figcaption><\/figure>\n<\/div>\n<\/div>\n\n\n\n

PV and solar thermal are not interchangeable. Check what has actually been specified, which parts are within the installer\u2019s scope, and what performance has been estimated for your property.<\/p>\n<\/div>\n\n\n\n

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QUALITY \/ BEST PRACTICE<\/p>\n\n\n\n

Choose the installation route before work begins.<\/h2>\n<\/div>\n\n\n\n
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Whether the project is privately funded or supported by a scheme, an installer should explain the standards, certification, safety checks and responsibilities applying to that installation.<\/p>\n\n\n\n

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Competence & certification<\/h3>\n\n\n\n

Ask for appropriate electrical and renewable-system competence and evidence of installer certification where required for your chosen scheme or tariff.<\/p>\n<\/div>\n\n\n\n

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MCS & system standards<\/h3>\n\n\n\n

MCS-certified work is assessed against the relevant scheme requirements; confirm the applicable standard edition with the installer.<\/p>\n<\/div>\n\n\n\n

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Roof & electrical design<\/h3>\n\n\n\n

Mounting, weatherproofing, cable routing, circuit protection, earthing and manufacturer instructions must be coordinated.<\/p>\n<\/div>\n\n\n\n

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The paperwork<\/h3>\n\n\n\n

Ask who is responsible for the DNO process, handover documents, warranties and any grant or export-tariff application.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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02 \/ BEFORE YOU CONNECT<\/p>\n\n\n\n

The network operator needs to know what is being connected.<\/h2>\n<\/div>\n\n\n\n
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Your Distribution Network Operator (DNO) manages the local electricity network. Grid-connected generation needs the appropriate connection process so that the network can assess the installation.<\/p>\n\n\n\n

G98: small-scale connection and notification<\/h3>\n\n\n\n

The usual G98 route covers type-tested small-scale generation at or below 16 A per phase \u2014 approximately 3.68 kW AC on a single-phase supply. The required notification is normally made following installation and commissioning.<\/p>\n\n\n\n

G99: an application before connection<\/h3>\n\n\n\n

Larger or other qualifying installations need a G99 application and DNO approval in advance of the relevant connection or commissioning work. The installer must account for the complete proposed generation and storage arrangement.<\/p>\n\n\n\n

This threshold relates to the relevant AC connection characteristics, not simply the number of panels or their combined DC nameplate rating. Ask the installer to confirm the correct route for your project.<\/p>\n\n\n\n

Find your network operator<\/a> and see the government guidance on registering energy devices<\/a>.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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02 \/ THE CONNECTION PAPERWORK<\/p>\n\n\n\n

Keep the DNO documents with the installation records.<\/h2>\n\n\n\n
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\"DC
Warning label<\/figcaption><\/figure>\n<\/div>\n\n\n\n
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\"Ground-mounted
Ground-mounted array<\/figcaption><\/figure>\n<\/div>\n\n\n\n
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\"Roof
Roof-mounted array<\/figcaption><\/figure>\n<\/div>\n<\/div>\n\n\n\n

Ask your installer to give you the relevant DNO submission, notification or approval, alongside the inverter and protection details. If the system includes a battery, any export limitation or other generation, make sure the DNO paperwork describes the actual connection rather than PV alone.<\/p>\n<\/div>\n\n\n\n

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02 \/ EXPORT & METERING<\/p>\n\n\n\n

Getting paid for exported electricity.<\/h2>\n<\/div>\n\n\n\n
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Inform the supplier after installation, retain the installation date and documents, and make sure the export arrangement is fully set up rather than assuming that exported electricity automatically earns a payment.<\/p>\n\n\n\n

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Smart Export Guarantee<\/h3>\n\n\n\n

A participating supplier may pay eligible generators for metered electricity exported under its SEG tariff.<\/p>\n<\/div>\n\n\n\n

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Export MPAN<\/h3>\n\n\n\n

An export MPAN identifies the export metering point separately from the import account. The supplier and DNO can guide you through the allocation process.<\/p>\n<\/div>\n\n\n\n

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Evidence<\/h3>\n\n\n\n

The supplier may require acceptable installation certification, DNO documents and a meter capable of recording qualifying export data.<\/p>\n<\/div>\n\n\n\n

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Check the tariff<\/h3>\n\n\n\n

Export rates, terms and evidence requirements depend on the chosen supplier. Ask when the tariff starts and what readings will be used.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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02 \/ A USEFUL DISTINCTION<\/p>\n\n\n\n

Import and export are different metering records.<\/h2>\n<\/div>\n\n\n\n
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The electricity you buy from the grid and the electricity your solar system sends back are different flows. Import and export MPANs identify the associated metering points for industry administration.<\/p>\n\n\n\n

Export payments depend on a suitable metering arrangement, tariff eligibility and application. Your ordinary import bill or the presence of an inverter alone is not enough.<\/p>\n\n\n\n

More detail: MyWarmHome MPAN and DNO guide and Ofgem\u2019s Smart Export Guarantee information<\/a>.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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03 \/ AFTER INSTALLATION<\/p>\n\n\n\n

What should the homeowner be shown?<\/h2>\n\n\n\n

A suitable handover makes the installation understandable and serviceable. The installer should demonstrate the monitoring system, identify the isolation arrangements and explain what to do if a fault appears.<\/p>\n\n\n\n

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01<\/p>\n\n\n\n

Labels & isolation<\/h3>\n\n\n\n

Solar PV warnings, DC and AC circuit identification, accessible isolation and the relevant diagrams should be provided.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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02<\/p>\n\n\n\n

Cable management<\/h3>\n\n\n\n

PV leads should be supported and protected from abrasion, snagging, debris and damaging contact with roofing materials.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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03<\/p>\n\n\n\n

Inverter & protection<\/h3>\n\n\n\n

The inverter and protection equipment need suitable siting, fixing, access and manufacturer-specified clearances.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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04<\/p>\n\n\n\n

Monitoring & documents<\/h3>\n\n\n\n

Keep the generation\/monitoring information, test certificates, specifications, warranties and emergency instructions together.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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\"Solar
Isolation and labels<\/figcaption><\/figure>\n<\/div>\n\n\n\n
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\"Solar
Inverter fault indication<\/figcaption><\/figure>\n<\/div>\n\n\n\n
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\"Solar
Schematic diagram<\/figcaption><\/figure>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n
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03 \/ CHECKING PHYSICAL DETAILS<\/p>\n\n\n\n

Look at the roof and the electrical installation \u2014 safely.<\/h2>\n<\/div>\n\n\n\n
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Mounting and cabling should be checked by competent installers. A homeowner can understand the evidence, review photographs and make visual observations from safe locations without climbing onto the roof or opening electrical enclosures.<\/p>\n\n\n\n

Roof and array<\/h3>\n\n\n\n

Panel layout, secure mounting, roof weatherproofing, setbacks, shading, safe access and wind actions should match the project design and relevant product\/system instructions. There is no single roof-edge dimension or pitch that applies to every installation.<\/p>\n\n\n\n

Cables and protective devices<\/h3>\n\n\n\n

DC leads need safe support and suitable connectors. Isolation, protection, earthing and bonding should be designed, installed and tested for the particular electrical installation.<\/p>\n\n\n\n

Generation monitoring<\/h3>\n\n\n\n

Make sure you know how to review the inverter or app, locate any generation meter and contact the installer if a persistent warning or unexplained drop in output appears.<\/p>\n\n\n\n

Report signs of water ingress, visibly damaged components or unusual sounds or smells; do not investigate live electrical components yourself.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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03 \/ EXAMPLES FROM THE ORIGINAL GUIDE<\/p>\n\n\n\n

Array arrangement, metering and protective conductors.<\/h2>\n\n\n\n
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\"Solar\n\t\t\t\n\t\t\t\t\n\t\t\t<\/svg>\n\t\t<\/button><\/figure>\n<\/div>\n\n\n\n
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The original technical illustration is retained for reference.<\/p>\n\n\n\n

Keep the installed design on file<\/h3>\n\n\n\n

Ask for the final schematic, inverter and panel details, protection and isolation information, and any network-operator confirmation.<\/p>\n\n\n\n

Inspect, do not interfere<\/h3>\n\n\n\n

The roof and electrical equipment are specialist work areas. Photographs, clear labels and a proper handover are more useful than homeowner adjustments.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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\"Solar
Generation meter<\/figcaption><\/figure>\n<\/div>\n\n\n\n
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\"Generation
Metering equipment<\/figcaption><\/figure>\n<\/div>\n\n\n\n
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\"Protective
Protective bonding<\/figcaption><\/figure>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n
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03 \/ PANELS & CIRCUITS<\/p>\n\n\n\n

Series, parallel and inverter choices.<\/h2>\n<\/div>\n\n\n\n
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The installer should explain the chosen topology, shading assumptions and any optimisers or other equipment. Neither connection arrangement should be selected solely on a generic promise of better production.<\/p>\n\n\n\n

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Series strings<\/h3>\n\n\n\n

Modules connected in series raise string voltage while the same string current flows through them. Shade and panel mismatch can affect output.<\/p>\n<\/div>\n\n\n\n

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Parallel strings<\/h3>\n\n\n\n

Parallel branches increase the combined current at a broadly common voltage; cables and protection must suit the resulting arrangement.<\/p>\n<\/div>\n\n\n\n

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String inverter<\/h3>\n\n\n\n

One inverter processes the output of one or more designed DC strings. Its specifications and maximum-power-point tracking must suit the proposed array.<\/p>\n<\/div>\n\n\n\n

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Microinverters & hybrid systems<\/h3>\n\n\n\n

Microinverters convert power at individual modules; a hybrid inverter can be designed to manage compatible solar and storage equipment.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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INVERTERS \/ THE ORIGINAL IMAGES<\/p>\n\n\n\n

Three equipment arrangements to recognise.<\/h2>\n\n\n\n
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\"Solar
Microinverter<\/figcaption><\/figure>\n<\/div>\n\n\n\n
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\"Solar
Hybrid inverter<\/figcaption><\/figure>\n<\/div>\n\n\n\n
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\"Solar
Inverter<\/figcaption><\/figure>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n
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04 \/ ELECTRICAL STORAGE<\/p>\n\n\n\n

What can a battery add to a solar system?<\/h2>\n<\/div>\n\n\n\n
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A domestic battery can store some electricity generated during the day for later use. Its value depends on household demand, tariffs, usable capacity, round-trip losses, installation costs and how the controls operate.<\/p>\n\n\n\n

Check the usable storage and system design<\/h3>\n\n\n\n

Battery chemistries and product designs vary. Lithium-ion families are widely used in domestic systems; select equipment as part of a fully specified compatible installation rather than by nominal capacity alone.<\/p>\n\n\n\n

Do not assume backup is automatic<\/h3>\n\n\n\n

Some battery systems offer a backup supply during a power cut, but only when the relevant equipment, isolation and circuits have been designed for that function.<\/p>\n\n\n\n

Ask about future servicing<\/h3>\n\n\n\n

Check warranty conditions, monitoring, maintenance, emergency procedures and what happens at end of life.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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04 \/ STORAGE AND DIVERSION<\/p>\n\n\n\n

Battery, hybrid inverter or hot-water diverter?<\/h2>\n\n\n\n
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\"Home
Battery storage<\/figcaption><\/figure>\n<\/div>\n\n\n\n
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\"Solar
Power diverter<\/figcaption><\/figure>\n<\/div>\n\n\n\n
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\"Battery
Battery and inverter<\/figcaption><\/figure>\n<\/div>\n<\/div>\n\n\n\n

Battery storage retains electricity for later use. A surplus-power diverter redirects available electricity to a compatible load, often a hot-water immersion heater. They perform different tasks and can be considered separately or together where the design supports this.<\/p>\n<\/div>\n\n\n\n

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04 \/ BATTERY LOCATION<\/p>\n\n\n\n

Fire safety should be designed in from the start.<\/h2>\n<\/div>\n\n\n\n
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Battery capacity, design, environmental conditions and building layout should inform the location. Do not choose a spare cupboard or loft simply because it is convenient. BSI \u2014 PAS 63100:2024<\/a>.<\/p>\n\n\n\n

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PAS 63100:2024<\/h3>\n\n\n\n

This specification addresses fire safety for domestic electrical battery energy-storage systems, including location, equipment and protective measures within its scope.<\/p>\n<\/div>\n\n\n\n

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Suitable location<\/h3>\n\n\n\n

Outdoor siting is preferred where practicable under the PAS. Indoor locations need assessment against its specific restrictions, separation and ventilation requirements.<\/p>\n<\/div>\n\n\n\n

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Routes & neighbouring spaces<\/h3>\n\n\n\n

Bedrooms, escape routes, lofts\/roof voids and proximity to openings or stored flammable materials all need careful consideration against the applicable requirements.<\/p>\n<\/div>\n\n\n\n

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Emergency information<\/h3>\n\n\n\n

Ask the installer about warning notices, any detection arrangements, safe isolation and emergency instructions for the final location.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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04 \/ USE THE EXCESS<\/p>\n\n\n\n

What is a solar power diverter?<\/h2>\n<\/div>\n\n\n\n
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A power diverter detects surplus solar electricity and redirects it to a specified load, commonly an immersion heater, instead of exporting it immediately.<\/p>\n\n\n\n

This may help use more generation at home, but it should be compared with the export tariff, hot-water demand, existing heating arrangements and any battery already installed.<\/p>\n\n\n\n

Ensure the diverter, electrical circuit, immersion heater and any hot-water safety controls are compatible and correctly installed.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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04 \/ CERTIFICATES & SAFETY<\/p>\n\n\n\n

Keep evidence of the work and the checks.<\/h2>\n\n\n\n

Different electrical jobs can require different certification. Your electrician should identify the correct certificate for the work actually carried out.<\/p>\n\n\n\n

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01<\/p>\n\n\n\n

Installation certificate<\/h3>\n\n\n\n

An Electrical Installation Certificate is typically used for new circuits or other work requiring that form of certification.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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02<\/p>\n\n\n\n

Minor works<\/h3>\n\n\n\n

A Minor Electrical Installation Works Certificate may apply to certain additions or alterations to an existing circuit.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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03<\/p>\n\n\n\n

System handover<\/h3>\n\n\n\n

Keep commissioning results, system drawings, manuals, warranties and any applicable MCS certificate.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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04<\/p>\n\n\n\n

Network & export<\/h3>\n\n\n\n

Keep the DNO documents, metering information and any supplier export-tariff confirmation.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

Do not confuse product warranty documentation with electrical safety certification or network permission.<\/p>\n<\/div>\n\n\n\n

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HEALTH, SAFETY & ACCESS<\/p>\n\n\n\n

Protect the people, roof and services.<\/h2>\n<\/div>\n\n\n\n
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Working at height, roof condition, hidden materials and external services should be considered before the team starts. Contractors should explain access arrangements, site safety and any special hazards.<\/p>\n\n\n\n