This article was automatically translated from the original Turkish version.
In transmission and distribution lines, the network equipment used to hold conductors at a specified distance from each other in the air, and installed at the appropriate span and height along hat, is called a pole.
Foundation: Ensures the pole rests securely on the ground. It is in the form of a concrete block and transmits the pole’s load to the earth.
Pole Body: The main load-bearing component of the pole. It may consist of several sections depending on height. Typically made of steel or reinforced concrete.
Cross Arm: Horizontally mounted on the sides of the pole to support the conductors (wires). Maintains the proper spacing between conductors.
Insulator: Used to secure electrical conductors to the pole and provide electrical isolation from it. Made of porcelain, glass, or polymer material.
Conductor: Wires that carry electrical energy. May be made of aluminum, copper, or aluminum conductor steel-reinforced (ACSR).
Ground Wire (Shield Wire): Located at the top of the pole. Installed above the conductors to protect the line from lightning strikes. Connected to the grounding system.
Grounding System: Allows fault currents or leakage currents to be conducted into the earth. Typically constructed using copper rods or steel plates at the base of the pole.
Name Plate: Information related to the pole (type, identification number, manufacturer, year of manufacture, etc.) is marked on this plate.
Ladder and Safety Equipment (Optional): When maintenance on the pole is required, climbing aids such as steps, safety ropes, or rungs may be installed.
Poles used in energy transmission lines are made of wood, concrete, and iron.
Poles made from black pine, fir, larch, and juniper trees are called wooden poles. They are used in low and medium voltage overhead transmission and distribution lines. Due to their low mechanical strength, the spacing between poles must be carefully selected and the line height should not be excessive. They are subject to special treatments due to adverse effects from weather conditions and insects.
To prevent damage from rain or snowwater, the top of the pole is cut at a 45° angle. Their lengths range from 8 meters to 13.5 meters, and insulators are mounted directly onto the pole. Iron cross arms are used to carry the conductors. They are used up to a maximum voltage of 30 kV. In Türkiye, wooden poles are generally used temporarily in distribution networks and during emergency situations, and are later replaced.
Concrete poles are manufactured by mixing cement, aggregates, and admixtures in appropriate proportions and forming them into a cylindrical shape. These poles resemble low-voltage Type A iron poles in profile, and are designated with names such as Al, A2, A5, B3, B4, Cl, and C3. They have an average service life of 50 to 60 years. They are commonly used in low, medium, and high voltage applications. They are also preferred for street lighting, line terminations, and corner poles. They are produced using high-strength steel wires or steel rods. The cross arms on which insulators are mounted are made of concrete or iron. The foundation consists of concrete fill; their weights range from 250 kg to 3500 kg, lengths from 8 m to 26 m, and diameters up to 50 cm.
Iron poles are made of iron and steel and are used in low, medium, and high voltage applications. Their foundations are filled with concrete and must have a minimum depth of 150 cm depending on the maximum height. I, U, and L-shaped profiles are used in their construction. Iron poles are classified into three types: A-type and lattice poles, pipe poles, and putrel poles.
Supporting Poles: Poles used along the route to carry conductors are called supporting poles. Poles used where the line changes direction slightly along the route are called corner supporting poles; these are poles where conductors are connected to insulators via supporting hardware.
Dead-End Poles: Poles that anchor and tension the conductors suspended from supporting poles at fixed points along the line. Poles used at the beginning and end of overhead lines, where conductors are terminated or tensioned via final connections to insulators, are called terminal poles.
Branch Poles: Supporting and corner supporting poles located at points where overhead lines split into branches. These poles may also carry additional equipment such as disconnectors or circuit breakers.
Distribution Poles: Poles used where more than two terminal connections branch off from an overhead line. These are also called division or distribution poles. The line with the largest cross-section is considered the main line, and all other lines are regarded as branches of this main line.
Transit Poles: Special poles manufactured to cross features such as water channels, straits, highways, railways, or other obstacles along the energy transmission line route.
Common Poles: Poles that carry both low-voltage and medium-voltage networks on the same structure are called common poles. Common poles are typically used in distribution areas, urban centers, and lighting systems.
Lighting Poles: Poles used for street, road, park, commercial, and factory lighting. Lighting poles are manufactured either by mounting lighting fixtures on overhead line poles or by using underground cable systems.
Energy transmission systems consist of transmission and distribution networks. The distribution network is classified as low and medium voltage, while the transmission network is classified as high and extra-high voltage.
Poles used at low voltage levels up to 100–1000 volts can be made of wood, iron, or concrete. Sometimes both low-voltage and medium-voltage lines are strung on the same pole. The low-voltage network standards established by the Turkish Municipalities Bank specify separate lengths for short and long poles. In Türkiye, concrete poles are widely used in energy transmission lines and urban low-voltage networks. The first prefabricated vibrated concrete poles in Türkiye were manufactured by İlsu Company, established by the Turkish Municipalities Bank, and have been used in town network installations since 1950.
Medium voltage levels include 3 kV, 6 kV, 10 kV, 15 kV, 20 kV, 25 kV, 30 kV, 31.5 kV, 33 kV, and 34.5 kV. Medium voltage poles range in height from 9 meters to 25 meters and are manufactured from wood, concrete, or iron. Today, concrete and iron poles are the most commonly used. Wooden poles are used only for emergency situations and are later replaced by concrete or iron poles.
High voltage levels include 45 kV, 60 kV, 66 kV, 80 kV, and 110 kV. Different types of iron poles are used in high-voltage transmission lines. To protect iron poles from environmental factors, they are coated with paint and protective layers, which must be reapplied after specified intervals.
Parts of an Electrical Transmission Pole
Types of Poles by Material
Wooden Poles
Concrete Poles
Iron Poles
Types of Poles by Application
Types of Poles by Voltage Level
Poles Used in Low Voltage
Poles Used in Medium Voltage
Poles Used in High Voltage