Unconnected wire endpoint

Diagnostic signature

Unconnected wire endpoint

KiCad's Schematic Editor (eeschema) Electrical Rules Checker triggers this warning when a wire segment fails to terminate at a valid electrical node, leaving it floating in the schematic.

What it means

In KiCad's Schematic Editor (eeschema), the Electrical Rules Checker (ERC) evaluates the design for proper logical connectivity. It requires that every wire segment forms a complete electrical path by attaching to a valid node. The "Unconnected wire endpoint" warning signifies that one or both ends of a drawn wire do not terminate at an acknowledged connectivity target, such as a component pin, junction, power symbol, or net label. As a result, the tool considers the wire electrically floating and disconnected within the schematic.

Why it happens

This diagnostic is typically triggered by schematic editing actions that orphan a wire segment. A common cause is moving a symbol using the standard 'Move' command rather than the 'Drag' command, which detaches the component's pins from their routed wires. Deleting a symbol or net label without simultaneously removing the attached wiring will also leave endpoints dangling. Grid misalignment is another prevalent factor: if components are placed or wires are drawn on a non-standard grid (e.g., anything other than 50 mils or 1.27 mm), the wire may visually overlap a pin but fail to register the exact coordinates required for logical connection. Furthermore, drawing a short wire stub from a pin to indicate it is unused—instead of correctly applying a 'No Connect' flag to the pin itself—will trigger this warning.

Minimal reproduction

(kicad_sch (version 20231120) (generator eeschema)
  (wire (pts (xy 100 100) (xy 120 100)) (stroke (width 0) (type default)))
)

How to fix it

Eliminate the floating wire segment by properly terminating it to a component pin or label, deleting it if it is unnecessary, or restoring grid alignment to ensure connections snap correctly.

```KiCad Schematic
(kicad_sch (version 20231120) (generator eeschema)
)
```

Step 1

• Locate the precise schematic coordinates of the ERC marker indicating the dangling wire endpoint.

Step 2

• If the wire segment is superfluous, a remnant from a deleted component, or an incorrect attempt to mark a pin as unused, select the wire and delete it.

Step 3

• If the wire is intended to connect to a nearby pin but failed to establish a link, ensure that the schematic connection grid is set to the standard 50 mils (1.27 mm).

Step 4

• Select the unattached wire endpoint and snap it directly to the intended pin, junction, or label. A successful connection is confirmed when the small, hollow square at the wire's end disappears.

Step 5

• If a component pin is intentionally meant to be left open, remove any attached wire stubs and select the 'No Connect' flag tool, placing the 'X' symbol directly onto the unconnected pin.

Upstream references

Schematic Editor | master | English | Documentation - KiCad Docs

eeschema/erc/erc_item.cpp - KiCad Source Code