Power networks/Guidelines/Power lines

Power lines are essential parts of the energy network, carrying electricity from generation sites (power plants) to end users (homes, businesses, industries). Mapping them shows how electricity is distributed and supports uses like planning, emergency response, and data analysis.
Accurate mapping and tagging of power lines helps build an open, global view of electricity networks that is essential for understanding energy access, identifying gaps in connectivity, and supporting energy transition.
This page aims to offer clear guidelines on how to map and tag power lines. It’s designed for all mappers, including those with no technical background in energy.

Power lines pose serious safety risks, including electric shock and electrocution, that may lead to death.
All information gathering on site should be done from a safe distance and in full compliance with local laws and warning signs. Always stay alert and prioritize your safety while mapping near power infrastructure. Never enter fenced, restricted, or hazardous areas.
This documentation does not encourage or expect mappers to cross barriers or access private or protected property under any circumstances.
Covered features
This page focuses on how to map overhead power lines. These are visible wires, that we see every day in urban and rural areas, as well as in transmission corridors in nature. They are typically supported by poles or towers, and are easily identifiable as energy infrastructure.
In the following sections, we'll see how to identify power lines, tag their visible components, and map where they start and end.
This page does not however cover underground or underwater cables, which are tagged using power=cable
. While both lines and cables carry electricity, they differ in construction, location, and mapping and tagging practices.
How to find lines
To locate power lines that may need mapping, you can try the following approaches when looking at satellite imageryor surveying safely on the ground :
- Follow existing infrastructure. Many power lines are already partially mapped in OSM. By tracing them, you may spot missing segments, incomplete tagging, or unmapped branches.
- Check near substations. Most of the time, overhead lines connect to substations. Check the surroundings of existing substations for lines that may be missing or inaccurately mapped.
- Check near energy-related facilities. Power plants (nuclear, thermal, hydro, wind, solar) and large industrial sites are typically connected to the high-voltage transmission network. These areas are good places to find major power lines.
- Check in populated areas. Low-voltage distribution lines are commonly found in residential neighborhoods, commercial zones, and urban streets.
Additional note : If you're short on inspiration and cannot find what needs to be mapped, you can refer to Osmose in the topic Power, or to OpenInfraMap.
How to map
Common principles
Beginning and end of lines
Every overhead power line should have clearly defined start and end points. These typically connect to one of the following structures:
- A
power=plant
or apower=substation
. - A
line_management=*
structure. - A
power=terminal
point where the line ends into a building or transitions to an undergroundpower=cable
.
A good mapping practice is to only map what is visibly verifiable. You should trace a power line based on:
- The visible supports (towers or poles).
- Or clearly identifiable shadows of the wires in aerial imagery.
If the line becomes unclear due to missing or low-quality imagery, do not continue drawing the line blindly. Instead, stop at the last confirmed visible support.
Physical components of a line
A power line is made up of several physical elements. The most common are:
- Wires : Electricity conductors represented as a
and tagged with
power=line
orpower=minor_line
, according to the function and voltage of the line. - Supports : Structures represented as a Template:Icone. These are usually towers (
power=tower
) or poles (power=pole
) that hold the wires/conductors above the ground. - Insulators: They prevent electrical contact between the wires and their supports.
- Terminals : Points where a line ends or transitions from overhead to underground. They are tagged as
power=terminal
and represented as a.
Types of lines
Transmission and distribution lines
Power lines serve different functions depending on heir voltage and position in the grid:
- Transmission lines move high-voltage electricity over long distances, usually between power plants and substations. They are tagged with
power=line
and their support structures are usually different types of towers.
- Distribution lines carry mid and low-voltage electricity from substations to end users (homes, businesses, smaller industrial facilities). They are tagged with
power=minor_line
and their support structures are mostly poles, and less often smaller power towers
Knowing and adding the voltage=*
helps clarify the line’s role.
For more information on power line classification, please refer to the dedicated wiki page.
Types of lines | Transmission lines | Distribution lines |
---|---|---|
Where to find them | Near power plants, substations and big industrial facilities. In transmission corridors over big distances. | Near distribution substations, in cities and rural areas. Near final energy users. |
Illustration of lines | ![]() |
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Types of support | ![]() |
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Examples in satellite imagery | ![]() |
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Recommended mapping and tags | ![]() power=line & voltage=* ; ![]() power=tower
|
![]() power=minor_line & voltage=* ; ![]() power=pole
|
Lines, bays and busbars
Different types of power lines are mapped as , but they serve different purposes:
- As seen above, lines tagged with
power=line
orpower=minor_line
are overhead conductors used to carry electricity outside substations.

- Bays, tagged with
power=line
+line=bay
) are short internal segments within substations that connect incoming or outgoing lines to specific equipment (portals and transformers) within switchgear zones. They represent the entry/exit path of a line inside the substation.
- Busbars, tagged with (
power=line
+line=busbar
) are conductive bars that distribute electricity across multiple bays or components within a substation. They act as internal connection hubs.
Only bays and busbars are located inside substations. Properly mapping them as and adding appropriate tags, including
voltage=*
, improves the detail and topology of substations.
For more guidelines on substations, please refer to the dedicated wiki page.
Supports
Supports are the physical structures that hold up power lines above the ground. They are mapped as that is on the line
, and tagged based on their type:
power=tower
for metal towers, mostly on high voltage lines.power=pole
for utility poles, mostly on mid- and low voltage lines.power=portal
for line entry/exit frames, usually near substations.power=terminal
for transition points from overhead lines to underground or buildings.
They are key elements of the network and should be precisely placed in OSM, as tools like Osmose use them as quality indicators.
Power towers
power=tower
nodes represent tall, metallic lattice structures used to support high-voltage transmission lines. They are usually spaced far apart and appear on satellite imagery as star- or cross-shaped structures with visible shadows.
Key characteristics:
- Used for
power=line
(transmission) and sometimespower=minor_line
when strong support is needed, for instance when the line makes a sharp angle.
- Spaced regularly, but distance varies with terrain, voltage, and tower design. As an example, towers supporting a 220 kV transmission line on a flat ground can be spaced 250m-450m.
- Easily visible on aerial imagery due to size and geometry.
- Can include attributes such as:
operator=*
design=*
material=*
line_management=*
if applicable
Check more atttributs as well as different tower designs on the dedicated page.
Do not use voltage=*
on tower or poles, as this is tagged on the line itself.
Power poles
power=pole
represent smaller vertical structures, usually made of wood, concrete, or metal. They are used for medium- or low-voltage distribution lines and/or power=minor_line
, and are more common in urban and rural residential areas.
Key characteristics:
- Can appear as simple vertical lines in satellite imagery.
- Much closer spacing than towers. Poles may be 20m-150m apart.
- Occasionally used for high-voltage lines where towers are impractical.
They are mapped as , tagged with
power=pole
, and can use the same attributes as towers.
Power portals and insulators

power=portal
represents large structural frames used at the entry or exit points of substations. They support the conductors as they transition from overhead lines into substation equipment.
Key characteristics:
- Usually visible on aerial imagery due to their square or П-shaped structure.
- Mapped as a
connecting the two base
that are the portal's legs. If satellite imagery is not the best, the portal can be mapped as a single
.
- Often support a
power=insulator
in the middle of the structure, where the line connects. If satellite imagery is not the best and the portal is mapped as a single
, there is no need to add the insulator.
For more information on mapping power portals, please refer to Power networks/Guidelines/Substations
Power terminals

An indoor substation inside a building requires connections between outdoor power lines and indoor equipment.
This transition involves passing through building walls with specific insulation requirements.
Mapping terminals improves network continuity by marking the limit between visible overhead infrastructure and unmapped or underground segments.
Key characteristics:
- Found at the end of a line where it disappears underground or in a building.
- Often located near substations, buildings, or at the edge of urban zones.
Line management
Additional note on line management near a substation : Upon entering a substation, a power=line
with circuits=1
and cables=3
should be connected to a single power=insulator
.
In case you have to end a multiple circuits power line (for instance 2 circuits with 6 cables or more), it should split in several separate 1-circuit lines. Mind adding line_management=split
on the tower where the circuits split.
For more information on how a line should be mapped entering a substation, please refer to Power networks/Guidelines/Substations
Additional tagging
Here are some of the most commonly used tags that help add more detail to mapped power lines.
frequency=*
: standardised on national or regional level to ensure compatibility across the power grid.cables=*
: especially usefull in the case of line management.circuits=*
: espectially usefull in the case of line management.operator=*
: helps identify ownership and responsibilities, and supports data analysis by distinguishing networks managed by different entities
Some of this information can be collected through field surveys or by consulting documents and data from national or local energy operators.
For a full list of available tags and attributes, see the dedicated page.
Quality assurance
Common mistakes
Supports not positioned on the line:
Sometimes, power towers or poles are mapped as placed next to the power line instead of directly on it. This should be avoided. All towers and poles should be positioned on the line
.
A notable exception is for disconnected towers near substations, which serve as backup structures in case of failure on the active line.
Reference works
Other mapping guidelines
- Power networks/Guidelines
- Power networks/Guidelines/Substations
- Power generation/Guidelines/Hydropower
- Power generation/Guidelines/Solar plants