Plug-In Solar Glossary

A small inverter that converts the DC output of one or two solar panels into grid-synchronized AC at the panel itself, rather than at a central string inverter. In plug-in solar it is the system's brain: it performs the grid synchronization, output limiting and anti-islanding shutdown that make an outlet connection possible.

A mandatory protection that makes a grid-tie inverter stop exporting power within roughly two seconds of losing the utility grid reference. It prevents a solar system from energizing a de-energized line — protecting utility workers — and de-energizes the plug pins of a plug-in system almost immediately after disconnection.

The everyday name for plug-in solar installed on or beside a balcony — one to four panels on a railing or stand, a microinverter, and a cable to a household outlet. The German term Balkonkraftwerk (balcony power plant) named the category; Germany counts about one million registered systems and an estimated four million installed.

Describes a solar system whose inverter synchronizes with the utility grid and feeds power into the home's existing circuits, letting appliances draw solar first and grid power for the balance. Plug-in solar is grid-tied by definition — which also means it must shut down when the grid fails.

A system design in which a smart meter with current-transformer clamps measures household consumption in real time and throttles the inverter so production never exceeds what the home is using — no power flows out to the grid. US vendors such as CraftStrom sell zero-export kits in states without plug-in frameworks on this basis.

The share of a solar system's production that the household uses in real time rather than exporting. Self-consumed energy offsets electricity at full retail price; exported surplus earns little or nothing in most plug-in frameworks, making self-consumption the dominant economic variable after hardware cost.

The control algorithm by which an inverter continuously finds the voltage-current combination that extracts maximum power from a panel as light and temperature change. Multi-MPPT microinverters track each panel input independently, so shade on one panel does not drag down the others.

The Outline of Investigation for Plug-in Photovoltaic Systems, published by UL Standards & Engagement in December 2025 — the first US safety document written for the plug-in system as a whole rather than its components. State laws such as Utah's HB 340 reference it as the qualifying safety condition.

The established US safety standard for inverters, converters and interconnection system equipment — the document grid-tie inverters are listed against, covering grid synchronization and anti-islanding behaviour. An ETL or UL listing to UL 1741 is verifiable in public certification directories.

The National Electrical Code article governing solar photovoltaic systems in the US — conductor sizing, disconnects, grounding and installation requirements. Written for hardwired installations, it predates consumer plug-in systems, which is part of the gap UL 3700 was created to fill.

Watt-peak is a panel's DC nameplate rating under ideal lab conditions; watt AC is the inverter's continuous output to the home. They are different numbers by design: many kits carry more panel Wp than inverter AC capacity (over-paneling) to fatten production in mornings, evenings and winter.

Lithium iron phosphate battery chemistry, the standard in quality balcony storage. LFP cells resist thermal runaway at far higher temperatures than the NMC chemistry common in older power banks, cycle thousands of times, and hold up well outdoors with proper enclosure and temperature management.

A solar panel that harvests light on both faces, adding output from light reflected off surfaces behind it. Increasingly common in balcony kits, where vertical railing mounting places a bright building wall directly behind the panel's rear face.

Total system price divided by output capacity — the standard unit for comparing solar hardware value. Meaningful only within a configuration class: comparing a bare inverter, a complete kit and a battery system on price per watt produces nonsense, because the denominator buys different things.

A billing arrangement in which exported solar energy earns credit against consumed grid energy, historically at or near retail rates. Most plug-in solar frameworks do not include net metering: exported surplus is typically uncompensated, which is why self-consumption dominates the economics.

An ingress-protection classification meaning fully dust-tight (6) and protected against water jets from any direction (5). For balcony solar, IP65-class enclosures are the practical benchmark for microinverters and batteries that live outdoors year-round.

Schuko is the standard continental European household plug; Wieland is a dedicated, shrouded energy socket installed by an electrician specifically for feed-in devices. German practice allows qualifying balcony systems on Schuko up to 800 W, while Wieland connections are recommended — and sometimes required by landlords or utilities — especially at higher outputs.

The UK's connection standard for small grid-tied generators up to 16 A per phase, administered through Distribution Network Operators (DNOs). The UK's planned plug-in solar route is being built through amendments to G98 and BS 7671, with a sub-800 W product specification under consultation.

The formal contract between a generator owner and their utility authorizing a grid-connected energy system, traditionally required for rooftop solar. State plug-in solar laws typically work by exempting qualifying small systems from exactly this requirement — Utah's HB 340 is the template.

The fraction of energy that survives the journey into and back out of a battery, including conversion losses in both directions. Marketing figures quote ideal conditions; independent measurements of balcony storage under real household loads land meaningfully lower — roughly 70-85%, with low-power night-time discharge the worst case.