Ground Symbol
Definition: The Ground symbol represents the reference node in a circuit diagram at which voltage is defined as zero volts (0 V), drawn as a series of three or more decreasing-length horizontal lines stacked vertically (earth ground) or as a downward-pointing triangle / three-pronged fork (signal/common ground) per IEC 60617-02 and ANSI Y32.2 / IEEE 315-1975; it is annotated GND or the earth symbol ⏚ and serves as both the common return path for current and, in safety earthing, a direct connection to the physical earth.
Also known as: GND symbol, earth symbol, earth ground symbol, chassis ground symbol, signal ground symbol, common ground symbol, ⏚ symbol circuit, electrical ground symbol meaning.
What the Ground symbol means
The ground symbol marks the node in a schematic that all other voltages are measured relative to. Because voltage is always a potential difference between two points, designers designate one node as 0 V — the ground reference — so that every other node can be described by a single voltage value (e.g. '5 V', '−12 V'). This convention eliminates the need to draw a return wire to every power source, greatly simplifying schematics.
There are several distinct ground types, each with its own symbol variant: earth ground (or safety ground) represents a physical connection to the Earth via a ground rod or building earthing system, providing a fault-current path for personnel safety; chassis ground represents a connection to the metal enclosure (chassis) of equipment; signal ground (or common ground) is the circuit's internal 0 V reference node with no mandatory connection to Earth. Using the wrong ground symbol — particularly confusing signal ground with safety earth — is a critical documentation error with safety implications.
How to identify the Ground symbol
The earth ground symbol is drawn as a horizontal line (the lead) terminating in a downward stack of three horizontal lines that decrease in length from top to bottom, creating a tapered or triangular profile — similar in appearance to stacked decreasing steps or a downward-pointing comb. The Unicode character ⏚ (U+23DA) represents this glyph in text. The chassis ground symbol uses three lines angled outward at 45° from a common point (resembling a pitchfork or arrow-head with fins), clearly distinguishable from the tapered-stack earth ground. The signal / common ground symbol is a plain downward-pointing filled or open triangle with a flat base and a connecting lead at the apex. All three variants share the downward orientation and single connecting lead, but differ in the terminal glyph shape.
Function and usage boundary
The ground symbol in a schematic performs two roles depending on context. As a circuit reference, it marks the 0 V node that serves as the common return path for all currents in the circuit; every power supply, voltage measurement, and signal level is defined relative to this point. As a safety earth connection, it provides a low-impedance path from exposed conductive parts of equipment to the physical Earth, ensuring that a fault — such as a live conductor contacting a metal chassis — causes a large fault current that trips a protective device (fuse or circuit breaker) rather than presenting a shock hazard to a person touching the equipment.
Standards: IEC vs ANSI
| IEC 60617 | IEC 60617-02 (Symbol 02-15-01) defines the earth (ground) symbol as three decreasing-length horizontal lines stacked below the connecting lead. IEC 60417 further distinguishes protective earth (PE, symbol IEC 60417-5019, the circle with a horizontal line and three decreasing lines below), functional earth (FE, symbol IEC 60417-5020), and chassis/frame ground. IEC colour code for the protective earth conductor is green-and-yellow (IEC 60446 / IEC 60445). |
|---|---|
| ANSI/IEEE 315 | ANSI Y32.2-1975 / IEEE 315-1975 defines the earth ground symbol as three decreasing horizontal lines (identical appearance to IEC). The chassis ground symbol in IEEE 315 uses lines angled at 45° from a point. Signal or common ground may be shown as a plain downward triangle. IEEE Std 91-1984 and ANSI/IEEE C37.2 address protective ground in power system schematics. |
| Key difference | The basic earth ground glyph (three decreasing horizontal lines) is visually identical in IEC 60617 and ANSI Y32.2 / IEEE 315. Differences appear in the variants: IEC 60417 has formal symbols for protective earth (PE) and functional earth (FE) with distinct graphical forms; ANSI / IEEE 315 uses the chassis ground pitchfork symbol and the signal ground triangle, which are widely used in North American electronics schematics. In practical CAD tools, the earth ground, chassis ground, and signal ground symbols coexist regardless of regional standard. |
The displayed SVG is the live editor implementation, not a licensed reproduction or certification of an IEC or IEEE database glyph. Verify the exact official entry and project edition before issuing work.
Logical terminals
| Logical ID | Editor terminal name |
|---|---|
| gnd | GND |
Where the Ground symbol is used
- Power supply circuits: the negative terminal of a DC supply is labelled GND and serves as the 0 V reference for all signal and power measurements in the circuit
- Safety earthing in mains-powered equipment: a protective earth (PE) connection from the metal chassis to the building earthing system, required by IEC 60364 and NEC Article 250
- Mixed-signal PCBs: separate analog ground (AGND) and digital ground (DGND) planes joined at a single star point to prevent digital switching noise from corrupting analog signal paths
- Chassis ground connections on automotive wiring diagrams, where the vehicle body serves as the negative return conductor for all circuits
- RF circuits where a ground plane provides a low-impedance return path and shielding for high-frequency signals
- Differential amplifier circuits where a virtual ground (typically at mid-supply voltage) provides the reference for signal measurement
Key facts
- The earth ground symbol is three decreasing-length horizontal lines stacked below a connecting lead, standardised in IEC 60617-02 and ANSI Y32.2 / IEEE 315-1975; the Unicode representation is ⏚ (U+23DA).
- Ground defines the 0 V reference node in a schematic; all voltages in the circuit are measured relative to this node.
- Three distinct ground symbol variants exist: earth ground (safety, physical connection to Earth), chassis ground (connection to equipment enclosure), and signal ground / common ground (circuit 0 V reference with no mandatory Earth connection).
- The single connecting pin of the ground symbol is labelled GND (pin id 'gnd') and connects to the top of the stacked-lines glyph, with the decreasing lines below.
- Protective earth (PE) conductors are colour-coded green-and-yellow per IEC 60446 in Europe and international installations, and green (or bare copper) per NEC in the United States.
- Confusing signal ground with safety earth (protective earth) in a schematic is a critical error: safety earth must carry fault currents to trip protection devices, while signal ground carries only return currents from circuit operation.
- IEC 60417-5019 defines the formal protective earth symbol (circle with a horizontal crossbar and three decreasing lines) used on equipment labels, distinct from the schematic symbol in IEC 60617-02.
- In PCB design, a ground plane (large copper fill connected to GND) reduces electromagnetic interference (EMI) and provides a low-impedance return path for high-frequency currents.
Diagrams that use this symbol
- xnx xnx transmitter wiring diagram
- circuit diagram
- and circuit diagram
- wiring diagram
- electrical connection diagram
- ignition diagram
- 3 way switch wiring
- wiring a three way switch
Frequently asked questions
What does the ground symbol look like in a circuit diagram?
The earth ground symbol looks like a horizontal line (the connecting lead) with three shorter horizontal lines stacked below it, each line shorter than the one above — forming a tapered downward shape. The chassis ground symbol uses lines angled outward like a pitchfork. The signal ground symbol is a downward-pointing triangle. All three variants have a single connecting lead at the top.
What does the ground symbol mean in a circuit?
The ground symbol marks the node defined as 0 V — the reference point against which all other voltages in the circuit are measured. It also shows where current returns to complete a circuit. In mains-powered equipment, the earth ground symbol additionally indicates a safety connection to the physical Earth, providing a fault-current path that causes protective devices to trip.
What is the difference between earth ground, chassis ground, and signal ground symbols?
Earth ground (three decreasing horizontal lines) represents a physical connection to the Earth and is used for safety earthing. Chassis ground (angled lines from a point, like a pitchfork) represents a connection to the metal enclosure of equipment. Signal ground (downward triangle) is the circuit's internal 0 V reference with no mandatory physical Earth connection. Using the wrong symbol misrepresents the safety intent of the connection.
What is the IEC vs ANSI difference for the ground symbol?
The basic earth ground glyph — three decreasing horizontal lines — is visually identical in IEC 60617-02 and ANSI Y32.2 / IEEE 315-1975. The main differences are in the variant symbols: IEC 60417 provides formal protective earth (PE) and functional earth (FE) symbols with distinct shapes used on equipment labels; ANSI / IEEE 315 defines the chassis ground pitchfork and signal ground triangle that are widely used in North American electronics schematics.
What standard defines the ground symbol?
The earth ground schematic symbol is defined in IEC 60617-02 (internationally) and ANSI Y32.2-1975 / IEEE 315-1975 (North America). The protective earth equipment marking symbol (the circle with crossbar and lines) is defined in IEC 60417-5019. NEC Article 250 and IEC 60364 govern the physical wiring requirements for safety earthing.
Why are there multiple different ground symbols on the same schematic?
Different ground symbols indicate different types of ground connections that must not be confused. A schematic may show safety earth (protective earth, PE) at the chassis and mains earth terminal, chassis ground at the equipment frame, and signal ground (or analog/digital ground) at internal circuit 0 V nodes. Each symbol communicates a different safety and functional requirement to the reader and installer.
What colour is the ground wire according to electrical standards?
Per IEC 60446 (used in Europe and most international installations), the protective earth (PE) conductor is identified by green-and-yellow stripes. Per NEC Article 250 (USA), the equipment grounding conductor is green, green with a yellow stripe, or bare (uninsulated) copper. These colour codes apply to physical wiring, not to the schematic symbol.
Related symbols
- Ground (Chassis) symbol
- Ground / Earth symbol
- Ground (Signal) symbol
- Outlet symbol
- Switch (3-Way) symbol
- Switch (SPST) symbol
Physical breadboard, PCB, and panel mapping
No universal physical profile is published for this symbol yet. Create a versioned custom part from the exact manufacturer dimensions and terminal map before fabrication.
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