Glossary
The terms you'll meet when buying plug-in solar, each explained in a sentence.
- Anti-islanding
- An inverter's automatic shut-off when the mains supply fails, so it can't feed power into a dead network. Also called loss-of-mains protection.
- Bifacial
- A bifacial solar panel generates electricity from light reaching both its front and its back.
- BS 1363
- The British Standard for UK 13 A plugs, sockets and fuses. Plug-in kits need a BS 1363-1 plug in a fixed BS 1363-2 socket.
- Clipping
- When panels could produce more power than the inverter's maximum output, the extra is cut off. This is called clipping.
- DNO
- Distribution Network Operator: the company that runs the local electricity network in your area. You must tell it about your plug-in solar kit.
- ENA Type Test Register
- The Energy Networks Association's public list of type-tested generation devices. Plug-in kits must be listed on it as Compliant.
- Export limitation
- Capping how much electricity a system sends out to the grid, which is not the same as capping how much it generates.
- G98
- The GB network rules for connecting small generators, including plug-in solar kits, in parallel with the local electricity network.
- Interim Product Specification
- The DESNZ rules a plug-in solar kit must meet before it can legally be installed and used in Great Britain.
- IP rating
- An Ingress Protection code showing how well a product keeps out dust and water. Plug-in kits need IP55 or better outdoors.
- kWh
- Kilowatt-hour: a unit of energy equal to using 1 kW for one hour. It's what your electricity bill charges for.
- kWp
- Kilowatt-peak: the rated DC power of solar panels under standard test conditions, used to describe the size of a solar array.
- MC4
- A common type of weatherproof, snap-together DC connector used on solar panel cables.
- Microinverter
- A small inverter that turns DC power from one or a few panels into mains AC. In a plug-in kit it enforces the 800 W output limit.
- MPAN
- Meter Point Administration Number: the unique reference for your home's electricity supply point.
- Permitted development
- Building work you can do without applying for planning permission, within set limits. In England it now names plug-in solar.
- Price cap
- Ofgem's quarterly limit on the unit rates and standing charges suppliers can charge on default energy tariffs in Great Britain.
- RCD
- Residual current device: a safety switch that cuts the power if current leaks to earth. Plug-in solar needs modern RCD protection.
- Self-consumption
- The share of your solar output that you use in your home as it's generated, rather than sending it to the grid.
- Smart Export Guarantee
- The GB scheme that pays for renewable electricity exported to the grid. Plug-in solar kits don't normally qualify.