{"schemaVersion":1,"slug":"utility-grid-connection","name":"Utility grid connection","kind":"symbol","abbreviation":"GRID","aliases":["utility source","mains supply","network infeed"],"category":"microgrid-systems","drawingTypes":["SLD"],"referenceFamilies":["IEC","IEEE / ANSI"],"summary":"The symbol for the external utility network as a supply source at the top of a single-line diagram.","description":["The utility grid connection symbol represents the public supply network as seen from the installation. It is drawn at the top or edge of a single-line diagram to show where power enters, and in a microgrid it is one of several sources, typically the reference source when the microgrid is grid-connected.","Common forms include a lattice tower glyph, a circle with a sine wave, a set of arrows into the busbar or a box labelled UTILITY or GRID. Voltage, prospective fault level and earthing system of the supply are written beside it.","The symbol does not show the network operator protection or reclose behaviour, which affects whether downstream generation must disconnect quickly. Those details come from the connection agreement and are usually noted on the drawing."],"readingNotes":["Read the fault level and X/R ratio noted beside the source.","The earthing system of the supply affects downstream design."],"drawingChecklist":["State voltage, fault level and earthing system.","Show incoming protection and metering.","Reference connection agreement."],"distinction":"A utility connection represents the external network; a grid equivalent source is a study model with defined impedance.","facts":[{"label":"Represents","value":"External supply network"},{"label":"Annotations","value":"Voltage, fault level, earthing system"},{"label":"Microgrid role","value":"Reference source when connected"},{"label":"Preview","value":"Independent educational illustration; consult the applicable standard and project legend for the exact graphic"}],"references":[{"sourceId":"pub-symbol-earthing-surge","relevance":"Public earthing and source symbol context."},{"sourceId":"pub-object-engineering-design","relevance":"Public electrical installation design references covering supply characteristics."}],"related":["point-of-common-coupling","grid-equivalent-source","three-phase-ac-source","substation"],"artwork":"s28-utility-grid-connection","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","plainEnglish":{"title":"What does Utility grid connection mean?","introduction":"The utility grid connection symbol represents the public supply network as seen from the installation. It is drawn at the top or edge of a single-line diagram to show where power enters, and in a microgrid it is one of several sources, typically the reference source when the microgrid is grid-connected.","example":"Common forms include a lattice tower glyph, a circle with a sine wave, a set of arrows into the busbar or a box labelled UTILITY or GRID. Voltage, prospective fault level and earthing system of the supply are written beside it.","drawings":"The symbol does not show the network operator protection or reclose behaviour, which affects whether downstream generation must disconnect quickly. Those details come from the connection agreement and are usually noted on the drawing.","terms":[{"name":"Terminal","meaning":"An identified point where a conductor connects."},{"name":"Rating","meaning":"A value stating the conditions for which equipment is specified."},{"name":"Schematic","meaning":"A drawing showing function and connections rather than physical appearance."}],"diagram":"flow","steps":["Identify the device and form","Read the connections and state","Check the equipment reference"],"caption":"A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.","sources":[{"label":"AutoCAD Electrical: Earthing, sources and surge protection","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-1E3FDEAE-B4B2-417C-8075-108AA2C6E509.htm"},{"label":"Electrical installation design methodology and references","url":"https://www.electrical-installation.org/enwiki/General_rules_of_electrical_installation_design"}],"detail":"The symbol for the external utility network as a supply source at the top of a single-line diagram. A utility connection represents the external network; a grid equivalent source is a study model with defined impedance.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/utility-grid-connection","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/utility-grid-connection.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"pub-symbol-earthing-surge","title":"AutoCAD Electrical: Earthing, sources and surge protection","publisher":"Autodesk","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-1E3FDEAE-B4B2-417C-8075-108AA2C6E509.htm","type":"cad-reference","scope":"Public vendor catalogue naming and functional variants. Vendor block names are not IEC identifiers. Linked for reference; no graphics or CAD files are redistributed.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Public earthing and source symbol context."},{"id":"pub-object-engineering-design","title":"Electrical installation design methodology and references","publisher":"Schneider Electric — Electrical Installation Guide","url":"https://www.electrical-installation.org/enwiki/General_rules_of_electrical_installation_design","type":"manufacturer","scope":"Public design context. No universal working clearance, equipment dimension or project compliance conclusion is asserted.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Public electrical installation design references covering supply characteristics."}]}