Editing Utility pole (section)

==Description==
[[File:Old steel pole - Gryfow 3.jpg|thumb|upright=0.7|Steel utility pole for low voltage in [[Gryfów]], Poland]]
The standard utility pole in the United States is about {{cvt|35|ft|-1}} tall and is buried about {{cvt|6|ft|0}} in the ground.<ref name="Florida">{{cite web|url=http://www.psc.state.fl.us/ConsumerAssistance/UtilityPoleDescriptions|title=What's on a utility pole?|year=2008|publisher=Florida Public Service Commission|archive-url=https://web.archive.org/web/20160225175755/http://www.psc.state.fl.us/ConsumerAssistance/UtilityPoleDescriptions|archive-date=2016-02-25|url-status=live|work=Consumer Assistance|access-date=2008-10-24}}</ref> In order to meet clearance regulations, poles can, however, reach heights of at least 120 feet (40 meters). They are typically spaced about {{cvt|125|ft|-1}} apart in urban areas, or about {{cvt|300|ft|-2}} in rural areas, but distances vary widely based on terrain. Joint-use poles are usually owned by one utility, which leases space on it for other cables. In the United States, the [[National Electrical Safety Code]], published by the [[Institute of Electrical and Electronics Engineers]] (IEEE) (not to be confused with the [[National Electrical Code]] published by the [[National Fire Protection Association]] [NFPA]), sets the standards for construction and maintenance of utility poles and their equipment.

===Pole materials===
Most utility poles are made of wood, pressure-treated with some type of [[Wood preservation|preservative]] for protection against rot, fungi and insects. [[Southern yellow pine]] is the most widely used species in the United States; however, many species of long straight trees are used to make utility poles, including [[Douglas fir]], [[jack pine]], [[Pinus contorta|lodgepole pine]], [[Thuja plicata|western red cedar]], and [[Abies amabilis|Pacific silver fir]].

Traditionally, the preservative used was [[creosote]], but due to environmental concerns, alternatives such as [[pentachlorophenol]], copper [[naphthenic acid|naphthenate]] and [[borate]]s are becoming widespread in the United States. In the United States, standards for wood preservative materials and wood preservation processes, along with test criteria, are set by [[American National Standards Institute|ANSI]], [[ASTM International|ASTM]], and [[Wood preservation#American Wood Protection Association|American Wood Protection Association]] (AWPA) specifications. Despite the preservatives, wood poles decay and have a life of approximately 25 to 50 years depending on climate and soil conditions, therefore requiring regular inspection and remedial preservative treatments.<ref>{{cite web|url=http://www.pmcpole.com/cms/AWPA_poleMaintenance_paper.pdf|title=PMCPOLE.COM|website=www.pmcpole.com|url-status=live|archive-url=https://web.archive.org/web/20110715094205/http://www.pmcpole.com/cms/AWPA_poleMaintenance_paper.pdf|archive-date=2011-07-15}}</ref><ref>{{cite web|url=http://www.pmcpole.com/cms/groundlineTreatmentSP.pdf|title=PMCPOLE.COM|website=www.pmcpole.com|url-status=live|archive-url=https://web.archive.org/web/20090114191254/http://www.pmcpole.com/cms/groundlineTreatmentSP.pdf|archive-date=2009-01-14}}</ref><ref>{{cite web|url=http://www.pmcpole.com/cms/rus_bulletin_1730B_121.pdf|title=PMCPOLE.COM|website=www.pmcpole.com|url-status=live|archive-url=https://web.archive.org/web/20090114191256/http://www.pmcpole.com/cms/rus_bulletin_1730B_121.pdf|archive-date=2009-01-14}}</ref> [[Woodpecker]] damage to wood poles is the most significant cause of pole deterioration in some parts of the U.S.<ref>{{cite web |last1=Harness |first1=Rick |title=Raptor Electrocutions and Distribution Pole Types |url=https://web.archive.org/web/20160315140750/http://volgabirds.ru/user_files/ikar/TechBulletin_0ct_00.pdf |website=Volga Birds |publisher=North American Wood Pole Coalition |access-date=16 April 2025}}</ref>

Other common utility pole materials are aluminum, steel and concrete, with composites (such as [[fiberglass]]{{citation needed|date=May 2020}}) also becoming more prevalent.<ref>{{Cite journal |last1=Rasheed |first1=Rizwan |last2=Javed |first2=Hajra |last3=Rizwan |first3=Asfra |last4=Afzaal |first4=Muhammad |last5=Ahmad |first5=Sajid Rashid |date=April 2023 |title=Eco-sustainability analysis of precast-concrete utility poles manufacturing–A case study from Pakistan |url=|journal=Heliyon |volume=9 |issue=4 |pages=e14976 |doi=10.1016/j.heliyon.2023.e14976 |doi-access=free |issn=2405-8440 |pmc=10121627 |pmid=37095914|bibcode=2023Heliy...914976R }}</ref> One particular [[patent]]ed utility pole variant used in Australia is the [[Stobie pole]], made up of two vertical steel posts with a slab of concrete between them.

===Power distribution wires and equipment===
[[File:US utility pole - labeled.jpg|thumb|upright=1.1|Typical North American utility pole, showing hardware for a residential 240/120&nbsp;V split-phase [[service drop]]: <span style="color:red;">(''A'',''B'',''C'')</span> 3-phase primary distribution wires (mounted on a crossarm), <span style="color:red;">(''D'')</span> neutral wire, <span style="color:red;">(''E'')</span> [[fuse cutout]], <span style="color:red;">(''F'')</span> [[lightning arrester]], <span style="color:red;">(''G'')</span> single-phase distribution transformer, <span style="color:red;">(''H'')</span> ground wire to transformer case, <span style="color:red;">(''J'')</span> "triplex" service drop cable carries secondary current to customer, <span style="color:red;">(''K'')</span> telephone and cable television cables ]]
On poles carrying both electrical and communications wiring, the electric [[overhead power line|power distribution lines]] and associated equipment are mounted at the top of the pole above the communication cables, for safety. The vertical space on the pole reserved for this equipment is called the ''supply space''.<ref name="Florida" />  The wires themselves are usually uninsulated, and supported by [[insulator (electricity)|insulators]], commonly mounted on a horizontal beam ('''{{vanchor|Crossarm|text=crossarm}}'''). Power is transmitted using the [[three-phase electric power|three-phase]] system, with three wires, or phases, labeled "A", "B", and "C".

Sub transmission lines comprise only these 3 wires, plus sometimes an overhead ground wire (OGW), also called a "static line" or a "neutral", suspended above them. The OGW acts like a lightning rod, providing a low [[Electrical resistance and conductance|resistance]] path to ground thus protecting the phase conductors from lightning.

[[File:China utility pole.jpg|thumb|left|A joint-use utility pole in China]]

Distribution lines use two systems, either grounded-wye ("Y" on [[Circuit diagram|electrical schematics]]) or delta (Greek letter [[Delta (letter)|"Δ"]] on electrical schematics). A delta system requires only a conductor for each of the three phases. A grounded-wye system requires a fourth conductor, the [[Ground and neutral|neutral]], whose source is the center of the "Y" and is grounded. However, "spur lines" branching off the main line to provide power to side streets often carry only one or two phase wires, plus the neutral. A wide range of standard distribution voltages are used, from 2,400&nbsp;V to 34,500&nbsp;V. On poles near a [[service drop]], there is a pole-mounted step-down [[distribution transformer]] to transform the high distribution voltage to the lower secondary voltage provided to the customer. In [[North America]], service drops provide 240/120&nbsp;V [[Split-phase electric power|split-phase]] power for residential and light commercial service, using cylindrical single-phase transformers.  In Europe and most other countries, 230&nbsp;V [[three phase]] (230Y400) service drops are used. The transformer's primary is connected to the distribution line through protective devices called [[fuse cutout]]s. In the event of an overload, the fuse melts and the device pivots open to provide a visual indication of the problem. They can also be opened manually by [[lineman (technician)|linemen]] using a long insulated rod called a [[hot stick]] to disconnect the transformer from the line.

The pole may be [[ground (electricity)|grounded]] with a heavy bare [[copper]] or [[copper-clad steel]] wire running down the pole, attached to the metal pin supporting each insulator, and at the bottom connected to a metal rod driven into the ground. Some countries ground every pole while others only ground every fifth pole and any pole with a transformer on it. This provides a path for leakage currents across the surface of the insulators to get to ground, preventing the current from flowing through the wooden pole which could cause a fire or shock hazard.<ref name="Grigsby"/><ref name="Florida"/>  It provides similar protection in case of [[flashover]]s and lightning strikes. A [[surge arrester]] (also called a lightning arrester) may also be installed between the line (ahead of the cutout) and the ground wire for lightning protection. The purpose of the device is to conduct extremely high voltages present on the line directly to ground.

If uninsulated conductors touch due to wind or fallen trees, the resultant sparks can start [[wildfire]]s. To reduce this problem, [[Aerial bundled cable|aerial bundled conductors]] are being introduced.

===Communication cables===
The communications cables are attached below the electric power lines, in a vertical space along the pole designated the ''communications space''.<ref name="Florida" />  The communications space is separated from the lowest electrical conductor by the ''communication worker safety zone'', which provides room for workers to maneuver safely while servicing the communication cables, avoiding contact with the power lines.<ref name="Florida"/>

The most common communication cables found on utility poles are copper or [[fibre-optic cable]] (FOC) for [[telephone lines]] and [[coaxial cable]] for [[cable television]] (CATV).  Coaxial or optical fibre cables linking [[computer networks]] are also increasingly found on poles in urban areas. The cable linking the [[telephone exchange]] to local customers is a thick cable lashed to a thin supporting cable, containing hundreds of [[twisted pair]] [[subscriber line]]s. Each twisted pair line provides a single telephone circuit or [[local loop]] to a customer. There may also be FOCs interconnecting telephone exchanges. Like electrical distribution lines, communication cables connect to service drops when used to provide local service to customers.

===Other equipment===
Utility poles may also carry other equipment such as [[street light]]s, supports for [[traffic light]]s and [[Overhead line|overhead wires]] for [[electric trolley]]s, and [[cellular network]] antennas. They can also carry fixtures and decorations specific for certain holidays or events specific to the city where they are located.

Solar panels mounted on utility poles may power auxiliary equipment where the expense of a power line connection is unwanted.

Streetlights and holiday fixtures are powered directly from secondary distribution.