Solar Components
18 terms in the solar components category.
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AC Disconnect
An AC disconnect is a switch that isolates a solar inverter's AC output from the building service and the utility grid. NEC 2023 Article 705 sets disconnecting-means rules for interconnected sources, and many utilities also require a lockable, visible-blade switch near the meter so line workers can confirm the PV system is isolated.
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Ballasted Racking
Ballasted racking is a flat-roof PV mounting system held down by weight, usually concrete blocks, instead of roof penetrations. Ballast quantity comes from wind uplift and sliding checks under ASCE 7 Chapter 29 or the local code. It is common on commercial membrane roofs where owners want to avoid penetrating the waterproofing.
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BESS (Battery Energy Storage System)
A battery energy storage system (BESS) is a packaged set of batteries, power conversion equipment and controls that stores electricity and discharges it later. In the US, NEC Article 706 and UL 9540 govern installation and listing. Solar designers pair BESS with PV for backup power, peak shaving and time-of-use savings.
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Bypass Diode
A bypass diode is a diode wired across a group of series-connected cells, usually inside a PV module's junction box, that gives current a path around that group when it is shaded or damaged. It limits hot-spot heating. IEC 61215-2:2021 includes a bypass diode thermal test (MQT 18) for module qualification.
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Central Inverter
A central inverter is a large inverter, typically rated from several hundred kilowatts to a few megawatts, that converts DC from many combined strings into AC in one unit. It is common in utility-scale ground-mount plants. Safety standards include IEC 62109-1, and many units ship as skids with transformers and switchgear.
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DC Disconnect
A DC disconnect is a switch that isolates the DC conductors of a solar PV system from other equipment so they can be serviced safely. NEC 690.13 requires a disconnecting means for PV system conductors and NEC 690.15 covers equipment isolation. It must be rated for the maximum system voltage and current.
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Hybrid Inverter
A hybrid inverter is a single device that converts solar DC to AC, charges and discharges a battery, and can supply backup power during grid outages. In the US such units are listed to UL 1741, and they became more common after California's NEM 3.0 tariff in 2023 rewarded storing solar for self-use.
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Junction Box
A junction box is the sealed enclosure on the back of a PV module that houses the cell-string terminations, bypass diodes and output cables with connectors. IEC 62790 sets safety and test requirements for PV junction boxes, and a reliable box protects against moisture ingress, overheating and loss of bypass function.
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L-Foot / Stand-off
An L-foot or stand-off is the bracket that connects a roof attachment, usually lag-screwed into a rafter, to the racking rail of a pitched-roof solar array. It transfers wind and snow loads into the structure, and its spacing is checked against ASCE 7-22 design loads during permit engineering.
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MC4 Connector
MC4 is a single-contact DC connector for solar PV cables, originally made by Multi-Contact, now Stäubli, and widely copied as the industry's de facto standard. IEC 62852 sets requirements for PV DC connectors, and installers use MC4-type plugs to join modules, optimizers and string cables with locking, weatherproof connections.
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Microinverter
A microinverter is a small inverter installed at each PV module that converts DC to AC and runs maximum power point tracking for that module alone. Because each module's output is AC, microinverter systems readily meet NEC 2023 Section 690.12 rapid shutdown, and they suit shaded or complex residential roofs.
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Mounting Rail
A mounting rail is the extruded aluminium beam that holds PV modules and transfers their weight, wind, and snow loads to roof attachments or ground-mount posts. In the United States, rails that also bond module frames are commonly listed to UL 2703. Engineers size rail spans using ASCE 7 loads and the manufacturer's span tables.
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PCU (Power Conditioning Unit)
PCU stands for Power Conditioning Unit, the term Indian solar tenders and off-grid suppliers use for a solar inverter that combines MPPT charge control, battery charging and DC-to-AC inversion in one cabinet. In India, PV inverters including PCUs must meet the IS 16221 safety standard, the BIS adoption of IEC 62109, under compulsory registration.
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Pile Foundation (Ground Mount)
A pile foundation for a ground-mount solar plant is a steel post, screw pile or concrete pier that anchors fixed-tilt or tracker racking into the soil. Pile capacity is confirmed by field load tests such as ASTM D1143 (compression), D3689 (tension) and D3966 (lateral). Structural engineers size embedment depth from geotechnical data.
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PV Module
A PV module (photovoltaic module) is a sealed, framed assembly of solar cells that converts sunlight into DC electricity. Crystalline silicon modules are design-qualified under IEC 61215 (IS 14286 in India) and safety-qualified under IEC 61730. Designers use module datasheet values such as Voc, Isc and temperature coefficients to size strings and inverters.
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Solar Roof Flashing
Solar roof flashing is the metal or rubber-sealed component that waterproofs each point where a rooftop solar mount fastens through the roof. It slides under the roofing course above and over the course below, so water sheds past the fastener. The 2021 International Residential Code, Section R903.2, requires flashing at roof penetrations.
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Step-up Transformer
A step-up transformer raises the low-voltage AC output of solar inverters to a higher voltage for export, for example from 800 V to 33 kV or from 33 kV to 132 kV at the grid substation. Transformers are designed and tested to IEC 60076, and their losses and impedance feed the plant's energy and fault studies.
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String Inverter
A string inverter is an inverter that converts DC power from one or more series-connected PV strings into grid-synchronised AC power through built-in MPPT inputs. In the US it is listed to UL 1741 with IEEE 1547-2018 grid support; in India, safety follows IS 16221 (IEC 62109) and anti-islanding follows IS 16169.
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