How tall are high voltage power lines

Applies to phase wires 22kV and below. Vertical Clearances The governing standard for clearances between overhead utility facilities and land traversed by vehicles is the National Electric Safety Code NESC , which prescribes minimum requirements and is considered the industry standard for such clearances across the country.

NESC Rule covers the "vertical clearances of wires, conductors, cables, and equipment above ground, roadway, rail, or water surfaces. With respect to existing facilities, the code is revised on a continuing basis, and although these facilities are not technically required to comply with the latest editions, most installations provide adequate clearances for the appropriate nature of the surface.

Over time, these utility lines can sag below the original construction level, and the topography of the area can be altered due to changes in land usage. In addition, there is a worker safety zone located between the communication lines and the power lines to keep utility workers safe while performing repairs and installations. As the size of this safety area changes, so does the required height for power lines.

Telephone wires have the lowest requirements for ground clearance. Unfortunately, sometimes they struggle to keep up with changes. The NESC released a preview of the guidelines so utilities could weigh in on proposed changes.

According to the NESC, the standard height for a utility pole is 35 feet. In practical use, foot poles are the newest preferred model, though situations may call for poles of feet or higher. The NEC calls for various ground clearance limits for power lines based on voltage and location. These minimums differ slightly from those adopted by the NESC. There can also be different standards depending on whether the pole is carrying low- or high-voltage transmission lines.

This is the distance between the ground surface and the lowest point of the communication line. Companies plan on lines sagging over time due to the effects of gravity as well as temperature, bad weather and other factors.

The industry minimum for attachment points on a telephone pole is 18 feet on line lengths up to 20 feet. Longer stretches of wire experience more sag.

Lines up to feet in length should have minimum pole attachments of Other types of communication lines are heavier than telephone lines and so they are more susceptible to sag.

These lines call for even more caution to avoid violating minimum ground clearance codes. Telephone poles can be much shorter than electrical poles or joint utility poles. Several different types of power lines carry electricity from the power plant to individual businesses and homes. These include:. Low-voltage shock can be deadlier than high-voltage because of the impact on the heart. A child who sticks a toy into an electrical socket can be killed.

When it comes to danger, amps — the measure of how much current travels through the body — is more important than voltage. Stobie poles are single steel-reinforced concrete pole structures on which powerline conductors wires are mounted or strung.

Pole construction and type and number of insulators normally indicate the voltage of the powerline. Transmission towers are large steel structures that are used to carry high voltage powerlines. Transmission towers are usually found on the edge of or outside metropolitan areas. Insulators are used to separate bare conductors wires and cables from the stobie pole or tower structure. The higher the voltage carried by the conductor, the larger the insulators that are used to separate them from the pole or tower.

Insulators may be of a pin type one or a number of small discs mounted on a rigid pin or disc type larger discs that are attached to a wire. The number of disc insulators is usually indicative of the voltage of the powerline, eg 11 kV conductors are generally insulated by a single disc one disc for each wire.

Wire conductors may be insulated and bundled together, which is called an aerial bundled cable. The powerline may have between two and five conductors. Don't include any personal information. Essentially made of glass, fiber-optic cables cannot conduct electricity and are not affected by lightning. Adding telecommunication lines gets the most out of the large investment necessary to build transmission systems. Fiber-optic lines may be operated by the utility or leased to cable or phone companies.

The first rule of thumb: the higher the transmission tower, the greater the voltage. They're separated from towers by bell-shaped insulators known as "bells". For example, a line of 69, volts has four bells; , voltage has seven bells. But sometimes bells are added in case a utility wants to increase voltage later, so counting them isn't a surefire way to estimate voltage.

Towering transmission structures often double as weather data collectors. You may notice spinning cups of an anemometer measuring wind speed, or other meteorological equipment. You also may notice nesting birds, like hawks. Early tower designers discovered large birds like to build nests on the girders.

Birds can cause an outage if excreted waste lands on an insulator and triggers a short circuit. So to prevent random, potentially dangerous nesting, designers include special platforms for birds.