UGC
Underground cable
A cable route marked as buried in the ground, distinguishing direct-buried or ducted sections from overhead lines.
IEC
IEC · OHL
Overhead line
A line or route mark identifying conductors carried overhead on poles or towers rather than buried or enclosed.
In plain English
What does Overhead line mean?
The overhead line form identifies a circuit section strung in air between supports. On network single-line diagrams it distinguishes overhead feeders from underground cable sections, which matters because the two have different impedance, fault behaviour, auto-reclose practice and lightning exposure.
A simple example
The symbol does not tell you the conductor type, span lengths, earth wire arrangement or structure type. Line data sheets and route drawings carry those. Where a feeder changes from overhead to underground, look for a cable sealing end or transition point drawn at the junction.
What the drawings help you do
Note where the feeder changes between overhead and underground sections. Check whether auto-reclose is applied to feeders with overhead sections. An overhead line is strung in air; an underground cable is buried and has very different capacitance and fault characteristics.
This particular reference
A line or route mark identifying conductors carried overhead on poles or towers rather than buried or enclosed. An overhead line is strung in air; an underground cable is buried and has very different capacitance and fault characteristics.
- Terminal
- An identified point where a conductor connects.
- Schematic
- A drawing showing function and connections rather than physical appearance.
Read the source: IEC-60617 symbol preview directory · Building protection system
IEC · Overhead line route form
Independent IEC-context illustration; not certified IEC geometry.
Shown as an independently authored educational illustration. Use the cited publication and drawing legend to verify the required drafting form.
SLD / GA · OHL
What it represents
The overhead line form identifies a circuit section strung in air between supports. On network single-line diagrams it distinguishes overhead feeders from underground cable sections, which matters because the two have different impedance, fault behaviour, auto-reclose practice and lightning exposure.
The symbol does not tell you the conductor type, span lengths, earth wire arrangement or structure type. Line data sheets and route drawings carry those. Where a feeder changes from overhead to underground, look for a cable sealing end or transition point drawn at the junction.
How to read it
- Note where the feeder changes between overhead and underground sections.
- Check whether auto-reclose is applied to feeders with overhead sections.
Information to show or reference
- Identify conductor type and route length.
- Mark transition points to underground cable.
- Reference structure and earth-wire details on route drawings.
A distinction that matters
An overhead line is strung in air; an underground cable is buried and has very different capacitance and fault characteristics.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
IEC-60617 symbol preview directory
Public directory of IEC-oriented symbol families.
Building protection system
Public installation-guide context on lightning exposure of external conductors.
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.
Explore related references
Put the reference into a drawing workflow.
Elora Grid helps electrical teams work with drawings, specifications and equipment information. Explore the drafting workflow or join the early-access waitlist.