# Utility grid connection

Canonical URL: https://eloragrid.ai/symbols/utility-grid-connection
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: GRID
Drawing use: SLD
Reference families: IEC, IEEE / ANSI

The symbol for the external utility network as a supply source at the top of a single-line diagram.

## In plain English

### What does Utility grid connection mean?

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.

### A simple 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.

### What the drawings help you do

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.

### This particular reference

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.

### Terms

- Terminal: An identified point where a conductor connects.
- Rating: A value stating the conditions for which equipment is specified.
- Schematic: A drawing showing function and connections rather than physical appearance.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [AutoCAD Electrical: Earthing, sources and surge protection](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-1E3FDEAE-B4B2-417C-8075-108AA2C6E509.htm)
- [Electrical installation design methodology and references](https://www.electrical-installation.org/enwiki/General_rules_of_electrical_installation_design)


## What it represents

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.

## How to read it

- Read the fault level and X/R ratio noted beside the source.
- The earthing system of the supply affects downstream design.

## Information to show or reference

- State voltage, fault level and earthing system.
- Show incoming protection and metering.
- Reference connection agreement.

## Important distinction

A utility connection represents the external network; a grid equivalent source is a study model with defined impedance.

## Facts

- Represents: External supply network
- Annotations: Voltage, fault level, earthing system
- Microgrid role: Reference source when connected
- Preview: Independent educational illustration; consult the applicable standard and project legend for the exact graphic

## Public references

- [AutoCAD Electrical: Earthing, sources and surge protection](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-1E3FDEAE-B4B2-417C-8075-108AA2C6E509.htm) — Autodesk. Public earthing and source symbol context.
- [Electrical installation design methodology and references](https://www.electrical-installation.org/enwiki/General_rules_of_electrical_installation_design) — Schneider Electric — Electrical Installation Guide. Public electrical installation design references covering supply characteristics.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.