Wire Crossing (No Connection) Symbol
Definition: The Wire Crossing (No Connection) symbol represents two conductors that cross each other in a schematic diagram without making an electrical connection, used per IEC 60617 and ANSI Y32.2/IEEE 315 conventions to indicate that the crossing wires are electrically isolated from each other at the intersection point.
Also known as: crossover wire, no-connection crossing, bridge crossing, jump crossing, wire crossover, non-connected crossing.
What the Wire Crossing (No Connection) symbol means
The Wire Crossing (No Connection) symbol is a diagrammatic convention that allows two signal or power lines to pass over each other on a two-dimensional schematic without the reader assuming they share a node. In circuit diagrams it prevents ambiguity: without this symbol, every intersection of two drawn lines would require a dot (junction node) to confirm connection status.
The symbol enables schematic designers to route wires efficiently across a diagram without being constrained to avoid all crossings. When a crossing symbol is used, the reader knows definitively that the two conductors are separate nets. The four terminals—Top, Right, Bottom, and Left—represent the four wire ends entering the crossing point from each direction, with vertically-running wires passing over or under horizontally-running wires.
How to identify the Wire Crossing (No Connection) symbol
In the older ANSI convention a small arc (hump or bridge) on one of the crossing wires indicates no connection—the arc appears on the horizontal wire to show it 'jumps over' the vertical wire. In the modern IEC/ISO and IEEE convention (recommended since IEEE 315-1975) a plain cross with no dot is sufficient to indicate no connection; a dot is added only when wires ARE connected. The glyph has four terminals: Top, Right, Bottom, and Left, all at right angles to each other.
Function in a circuit
The wire-crossing symbol itself carries no electrical function—it is purely a diagrammatic drafting convention that routes two different nets past each other in 2D schematic space. In PCB CAD tools the crossing symbol maps to two separate net segments that do not share a netlist node, preventing the ERC (electrical rules check) from flagging an unintended short circuit.
Standards: IEC vs ANSI
| IEC 60617 | IEC 60617-02 (graphical symbols for diagrams: symbol elements, qualifying symbols) specifies that a simple line crossing without a dot represents no electrical connection. The hump/arc bridge symbol is not used in IEC drawings; a clean cross with no junction dot is the definitive IEC no-connection crossing. |
|---|---|
| ANSI/IEEE 315 | ANSI Y32.2-1975 (R1989) and IEEE 315-1975 originally used a small arc (hump) on one wire to indicate no connection; this convention was deprecated in favour of the dot-only-when-connected approach, but the hump symbol remains common in older drawings and some US textbooks. |
| Key difference | IEC uses a plain cross with no dot to indicate no connection; ANSI/older US practice uses a small arc (hump) on one wire to show no connection. Both conventions mean the same thing electrically. Modern EDA tools (KiCad, Altium, Eagle) use the IEC plain-cross convention. |
Terminals / pins
| Pin | Name |
|---|---|
| top | Top |
| right | Right |
| bottom | Bottom |
| left | Left |
Typical values
The wire-crossing symbol has no electrical values; it represents a purely topological relationship between two nets on a schematic diagram.
Where the Wire Crossing (No Connection) symbol is used
- Complex analogue circuit schematics where many signal traces must cross to reach their destination components
- Digital logic diagrams with multiple bus signals crossing data and control lines
- Power electronics schematics where high-side and low-side switch gate drive signals cross DC bus lines
- PCB schematic capture tools (KiCad, Altium, Eagle) where no-connection crossings ensure correct netlists
- Panel wiring diagrams showing multiple circuits routed through the same conduit or wiring field
- Ladder logic diagrams in PLC programming where rungs cross rail connections
Example
In a full-bridge motor driver schematic, four gate-drive signal lines from a gate driver IC cross the high-voltage DC bus lines; a wire-crossing (no connection) symbol at each intersection confirms that the gate signal nets are isolated from the power bus, preventing ERC errors in the CAD tool and ensuring correct PCB routing.
Key facts
- The Wire Crossing (No Connection) symbol has four terminals: Top, Right, Bottom, and Left, representing the four wire ends entering the crossover point from orthogonal directions.
- In IEC 60617-02 and modern EDA tools, a plain cross without a dot means no connection; a filled dot at an intersection always means the wires ARE connected.
- The older ANSI/IEEE practice used a small arc (hump) on one wire to show no connection, but this convention was deprecated in IEEE 315-1975 in favour of the dot-only-when-connected rule.
- A wire-crossing symbol carries no electrical function—it is a diagrammatic drafting device that routes two separate nets past each other in 2D schematic space.
- In EDA tools, forgetting a junction dot where wires should be connected is one of the most common schematic errors; the rule 'dot means connection, no dot means crossing' eliminates this ambiguity.
- The hump/bridge crossing symbol is still frequently seen in US educational textbooks and older industrial drawings, so schematic readers must determine which convention applies based on the drawing's title-block standard.
- Some schematic standards allow a slight gap (break) in one wire at a crossing as an alternative to the hump, indicating no connection; this approach is used in some European industrial drawings.
Frequently asked questions
What does the wire crossing symbol mean in a schematic diagram?
The wire crossing (no connection) symbol means two wires pass over each other on the schematic without making an electrical connection. The two conductors belong to different nets and are electrically isolated at the intersection point.
What does the wire crossing no-connection symbol look like?
In IEC 60617 and modern EDA tools, the no-connection crossing is a plain cross (+) with no dot at the intersection. In older ANSI/US drawings, a small arc (hump or bridge) on one wire indicates no connection. A filled dot at a crossing always means the wires ARE electrically connected.
What is the IEC vs ANSI difference for wire crossing symbols?
IEC 60617-02 and IEEE 315-1975 (current) use a plain cross with no dot to indicate no connection. Older ANSI and US textbook practice used a small arc or hump on one of the crossing wires. Both mean the same thing electrically; modern EDA tools universally use the IEC/IEEE plain-cross convention.
How do I know if two crossing wires in a schematic are connected or not?
If the intersection has a filled dot (junction dot), the wires are connected and share the same net. If there is no dot—just a plain cross or a hump—the wires cross without connecting. This dot convention is defined in IEC 60617-02 and IEEE 315.
Does the wire crossing symbol have an electrical value or function?
No. The wire crossing symbol has no electrical value or function. It is a purely graphical drafting convention used on 2D schematic drawings to route two separate nets past each other without implying an electrical connection.
What standard defines the wire crossing no-connection symbol?
IEC 60617-02 (graphical symbols for diagrams) defines the plain-cross no-connection convention. ANSI Y32.2-1975 and IEEE 315-1975 define both the current (no-dot = no connection) and historical (hump = no connection) conventions used in North American drawings.
How many terminals does the wire crossing symbol have?
The wire crossing symbol has four terminals: Top, Right, Bottom, and Left, representing the four wire ends entering the crossing point. The top and bottom terminals belong to one net; the left and right terminals belong to the other net; the two nets are not connected at the crossing.
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