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Fibre-optic connector
A demountable joint between optical fibres, drawn as a connector on a fibre link with an optical path mark.
IEC
Symbols · OF
Optical fibre cable
A cable line carrying light rather than current, used for protection signalling, SCADA links and substation process bus.
In plain English
What does Optical fibre cable mean?
The optical fibre cable representation marks a link that carries light signals. In power systems it is used for line differential protection signalling, IEC 61850 station and process bus networks, and links between buildings where electrical separation without a direct conducting path avoids earth potential rise problems. It is commonly drawn with a distinct line style or a small light-path mark on the conductor.
A simple example
Because the fibre carries no current, it must never be read as a power or earth path. The drawing should still give the fibre count, fibre type (single mode or multimode) and connector types at each end. Spare fibres and splice points are tracked in a fibre schedule rather than on the schematic.
What the drawings help you do
Do not treat the fibre as an electrical path for earthing or interlocking. Check fibre type and count against the equipment ports. An optical fibre cable carries light and gives electrical separation without a direct conducting path; a coaxial cable carries electrical signals and can transfer earth potential.
This particular reference
A cable line carrying light rather than current, used for protection signalling, SCADA links and substation process bus. An optical fibre cable carries light and gives electrical separation without a direct conducting path; a coaxial cable carries electrical signals and can transfer earth potential.
- Normally open / normally closed
- The contact state in the normal condition defined for the drawing.
- Terminal
- An identified point where a conductor connects.
- Signal
- Electrical information passed between devices, rather than necessarily the main power supply.
Read the source: IEC-60617 symbol preview directory · IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams
Schematic / SLD · OF
What it represents
The optical fibre cable representation marks a link that carries light signals. In power systems it is used for line differential protection signalling, IEC 61850 station and process bus networks, and links between buildings where galvanic isolation avoids earth potential rise problems. It is commonly drawn with a distinct line style or a small light-path mark on the conductor.
Because the fibre carries no current, it must never be read as a power or earth path. The drawing should still give the fibre count, fibre type (single mode or multimode) and connector types at each end. Spare fibres and splice points are tracked in a fibre schedule rather than on the schematic.
How to read it
- Do not treat the fibre as an electrical path for earthing or interlocking.
- Check fibre type and count against the equipment ports.
Information to show or reference
- State single mode or multimode and fibre count.
- Identify connector type at each end.
- Reference splice trays and patch panels in the fibre schedule.
A distinction that matters
An optical fibre cable carries light and gives galvanic isolation; a coaxial cable carries electrical signals and can transfer earth potential.
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.
IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams
Standards context for transmission-path graphics.
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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