Plug-In Solar Glossary
Every plug-in solar term in plain English. 36 terms and counting.
Regulation & Legal
- BS 7671— BS 7671:2018+A4:2026 — IET Wiring Regulations
- The UK national standard for electrical wiring in buildings. Amendment 4 (published 15 April 2026) added wiring rules for plug-in solar installations up to 800 VA.
- ESQCR— Electricity Safety, Quality and Continuity Regulations 2002
- UK regulations governing electrical safety on the network. SI 2026/848 amends these regulations to create the legal route for plug-in solar in Great Britain (not Northern Ireland).
- G98— Engineering Recommendation G98
- The process for notifying your DNO when you connect a small generator to the grid. For the plug-in solar route, check the 800 VA apparent-power limit and 16A per phase threshold. It is a notification, not an application.
- G99— Engineering Recommendation G99
- The process for connecting larger generators (over 16A per phase) to the grid. Requires DNO approval before connection, unlike G98 which is just a notification.
- IPS— Interim Product Specification
- The technical specification that plug-in solar devices must meet to be legally sold and used in Great Britain from 27 August 2026. Covers power limits, plug standards, safety, and labelling.
- PSSR— Plugs and Sockets etc. (Safety) Regulations 1994
- UK regulations governing the safety of plugs and sockets. SI 2026/848 amends these to create a route for approving plug-in solar devices that meet the IPS.
- SI— Statutory Instrument
- A form of secondary legislation made under authority of an Act of Parliament. SI 2026/848 is the statutory instrument that legalises plug-in solar in Great Britain.
- Type Tested— ENA Type Test Registration
- A process where inverters are tested against G98/G99 technical standards and registered on the ENA Connect Direct platform. Only type-tested devices are legal for plug-in solar.
Technical
- 13A— 13 amp plug or socket rating
- The standard current rating for normal UK household plugs and sockets. Plug-in solar and battery products should only use a suitable 13A socket exactly as the manufacturer instructs.
- 800 VA— 800 volt-amperes apparent power
- The maximum apparent-power limit used in the official plug-in solar interim product specification. Consumer kit listings often say 800W, but 800 VA is the precise term to check for legal compliance.
- AC— Alternating Current
- The type of electricity in your home wiring. Solar panels produce DC (direct current) which a microinverter converts to AC so it can feed into your household sockets.
- Anti-islanding— Anti-islanding protection
- A safety feature that automatically disconnects the solar inverter from the grid if the grid loses power. Required by the IPS to protect engineers working on the network.
- BS 1363— BS 1363 — British Standard for 13A plugs and sockets
- The British standard for the familiar 3-pin plug used in UK homes. Plug-in solar devices must use an approved BS 1363 plug to be legal.
- DC— Direct Current
- The type of electricity produced by solar panels. Must be converted to AC by a microinverter before it can be used in your home or fed to the grid.
- IP65— Ingress Protection rating IP65
- A dust and water resistance rating. IP65 usually means dust-tight and protected against water jets in test conditions, but the product manual still decides where it can safely be used.
- Isolation switch— Electrical isolation switch
- A switch used to disconnect equipment from the electrical supply for safety, maintenance, or emergency work. Some solar and battery installations need clearly labelled isolation points.
- kW— Kilowatt
- A unit of power equal to 1,000 watts. Used to describe the capacity of solar panels. An 800W system is 0.8kW.
- kWh— Kilowatt-hour
- A unit of energy. One kWh means using 1,000 watts for one hour. Your electricity bill is measured in kWh. A typical 800W plug-in solar system generates 600-900 kWh per year.
- LFP— Lithium iron phosphate
- A lithium battery chemistry commonly used in home storage. It is generally chosen for thermal stability and long cycle life, but it still needs correct charging, placement, and ventilation.
- Microinverter— Microinverter
- A small device that converts the DC electricity from a solar panel into AC electricity for your home. Plugs into a standard 13A socket. Must be type-tested and IPS-compliant.
- MPAN— Meter Point Administration Number
- The electricity supply identifier for your address. Bills may show a 21-digit "Supply Number" or "S Number"; the 13-digit MPAN core is the part usually needed on forms.
- MPPT— Maximum Power Point Tracking
- Electronics that help a solar panel operate at its most useful voltage and current as sunlight changes. More MPPT inputs can make mixed panel orientations easier to manage.
- PVGIS— Photovoltaic Geographical Information System
- A free tool from the European Commission that estimates solar energy generation for any location in Europe based on panel angle, orientation, and local weather data.
- RCBO— Residual Current Circuit Breaker with Overload protection
- A combined RCD and circuit breaker in one unit. Provides both earth fault protection and overload protection. May be specified for plug-in solar installations per the IPS.
- RCD— Residual Current Device
- A safety device that disconnects the electrical supply if it detects current leaking to earth, protecting against electric shock. The IPS specifies RCD/RCBO requirements for plug-in solar.
- VA— Volt-Ampere
- A unit of apparent power. The IPS limits plug-in solar to 800 VA maximum (approximately 800W). VA and watts are similar for solar inverters but VA is the technically correct unit.
Financial
- Load shifting— Load shifting
- Moving electricity use from expensive periods to cheaper periods. A home battery can charge overnight on a cheaper tariff and discharge later when grid electricity costs more.
- SEG— Smart Export Guarantee
- A government scheme that pays you for electricity you export back to the grid from your solar panels. SEG suppliers offer different rates (1p to 12p/kWh). You register after installing.
- Self-consumption— Self-consumption
- The proportion of solar electricity you use directly in your home rather than exporting to the grid. Higher self-consumption means more savings. A battery increases self-consumption from ~30% to ~60%+.
- Time-of-use tariff— Time-of-use electricity tariff
- An electricity tariff where the unit price changes by time of day. Batteries can use these tariffs by charging when electricity is cheap and discharging during expensive periods.
Organisations
- Connect Direct— ENA Connect Direct platform
- The online platform (connect-direct.energynetworks.org) where manufacturers register IPS-compliant plug-in solar devices. Replaced the old ENA Type Test Register in April 2024. Only registered devices are legal.
- DESNZ— Department for Energy Security and Net Zero
- The UK government department responsible for energy policy, including the legalisation of plug-in solar. Formerly known as BEIS.
- DNO— Distribution Network Operator
- The company that maintains the electricity cables to your home. Not your electricity supplier — they are different organisations. You notify your DNO after installing plug-in solar.
- ENA— Energy Networks Association
- The trade body representing UK electricity and gas network operators. Maintains the Connect Direct platform where manufacturers register compliant plug-in solar devices.
- MCS— Microgeneration Certification Scheme
- A certification scheme for renewable energy products and installers. Not required for plug-in solar DIY installations, but required for full rooftop solar systems to qualify for SEG.
- Ofgem— Office of Gas and Electricity Markets
- The UK energy regulator. Oversees the Smart Export Guarantee (SEG) scheme and energy supplier licensing.
Missing a term? Let us know. Put the terms in context: