PCC
Point of common coupling
A marker on a single-line diagram identifying where a customer installation or microgrid meets the public network.
SLD
Symbols · GRID
Utility grid connection
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.
- 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.
Read the source: AutoCAD Electrical: Earthing, sources and surge protection · Electrical installation design methodology and references
SLD · GRID
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.
A distinction that matters
A utility connection represents the external network; a grid equivalent source is a study model with defined impedance.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
AutoCAD Electrical: Earthing, sources and surge protection
Public earthing and source symbol context.
Electrical installation design methodology and references
Public electrical installation design references covering supply characteristics.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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