Hot stick
Encyclopedia
In the electric power distribution industry
, a hot stick is an insulated
pole, usually made of fiberglass
, used by electric utility workers when engaged on live-line working
on energized high-voltage electric power lines
, to protect them from electric shock
. Depending on the tool attached to the end of the hot stick, it is possible to test for voltage, tighten nuts and bolts, apply tie wires (twisted lengths of ductile wire which fasten the running cable to its supporting insulators), open and close switch
es, replace fuse
s, lay insulating sleeves on wires, and perform various other tasks while not exposing the crew to a large risk of electric shock
.
Hot sticks are made in different lengths, from a few feet long up to telescoping types of 30 feet length. Because the fiberglass provides electrical insulation
, the hot stick allows utility workers to perform operations on power lines safely without de-energizing them or while the state of the power line is not yet known. This is essential because certain operations (such as opening or closing combination fuse/switches) must occasionally be performed on an energized line. Additionally, after a fault occurs, the exact state of a line may not be certain; in this case, for reasons of crew safety, the utility workers must treat the line as though it were energized until it can be proven that it is not and safety ground cables can be applied to the line (so that the line is guaranteed to remain grounded/earthed
while maintenance is performed upon it).
If power tools are fitted to the end of the hot stick, they are usually powered hydraulically
rather than electrically because, like the fiberglass of the hot stick, the hydraulic fluid is also a good insulator. The hydraulic power is commonly supplied from the bucket truck (cherry picker
or aerial work platform
) supporting the workers.
The hot stick not only electrically insulates the worker from the energized conductor, it provides physical separation from the device being operated, to reduce the chances of burns which might result from electrical arcing
if there is a malfunction of the device being operated.
In the United States, ASTM Standard F 711 specifies the stringent requirements for hot sticks, and U.S. OSHA
standards require that they be inspected and electrically tested every two years.
Electricity distribution
File:Electricity grid simple- North America.svg|thumb|380px|right|Simplified diagram of AC electricity distribution from generation stations to consumers...
, a hot stick is an insulated
Electrical insulation
thumb|250px|[[Coaxial Cable]] with dielectric insulator supporting a central coreThis article refers to electrical insulation. For insulation of heat, see Thermal insulation...
pole, usually made of fiberglass
Fiberglass
Glass fiber is a material consisting of numerous extremely fine fibers of glass.Glassmakers throughout history have experimented with glass fibers, but mass manufacture of glass fiber was only made possible with the invention of finer machine tooling...
, used by electric utility workers when engaged on live-line working
Live-line working
In electrical engineering, live-line working is the maintenance of electrical equipment, often operating at high voltage, while the equipment is energised. The first techniques for live-line working were developed in the early years of the 20th century, and both equipment and work methods were...
on energized high-voltage electric power lines
Electric power transmission
Electric-power transmission is the bulk transfer of electrical energy, from generating power plants to Electrical substations located near demand centers...
, to protect them from electric shock
Electric shock
Electric Shock of a body with any source of electricity that causes a sufficient current through the skin, muscles or hair. Typically, the expression is used to denote an unwanted exposure to electricity, hence the effects are considered undesirable....
. Depending on the tool attached to the end of the hot stick, it is possible to test for voltage, tighten nuts and bolts, apply tie wires (twisted lengths of ductile wire which fasten the running cable to its supporting insulators), open and close switch
Switch
In electronics, a switch is an electrical component that can break an electrical circuit, interrupting the current or diverting it from one conductor to another....
es, replace fuse
Fuse (electrical)
In electronics and electrical engineering, a fuse is a type of low resistance resistor that acts as a sacrificial device to provide overcurrent protection, of either the load or source circuit...
s, lay insulating sleeves on wires, and perform various other tasks while not exposing the crew to a large risk of electric shock
Electric shock
Electric Shock of a body with any source of electricity that causes a sufficient current through the skin, muscles or hair. Typically, the expression is used to denote an unwanted exposure to electricity, hence the effects are considered undesirable....
.
Hot sticks are made in different lengths, from a few feet long up to telescoping types of 30 feet length. Because the fiberglass provides electrical insulation
Electrical insulation
thumb|250px|[[Coaxial Cable]] with dielectric insulator supporting a central coreThis article refers to electrical insulation. For insulation of heat, see Thermal insulation...
, the hot stick allows utility workers to perform operations on power lines safely without de-energizing them or while the state of the power line is not yet known. This is essential because certain operations (such as opening or closing combination fuse/switches) must occasionally be performed on an energized line. Additionally, after a fault occurs, the exact state of a line may not be certain; in this case, for reasons of crew safety, the utility workers must treat the line as though it were energized until it can be proven that it is not and safety ground cables can be applied to the line (so that the line is guaranteed to remain grounded/earthed
Ground (electricity)
In electrical engineering, ground or earth may be the reference point in an electrical circuit from which other voltages are measured, or a common return path for electric current, or a direct physical connection to the Earth....
while maintenance is performed upon it).
If power tools are fitted to the end of the hot stick, they are usually powered hydraulically
Hydraulic machinery
Hydraulic machines are machinery and tools that use liquid fluid power to do simple work. Heavy equipment is a common example.In this type of machine, hydraulic fluid is transmitted throughout the machine to various hydraulic motors and hydraulic cylinders and which becomes pressurised according to...
rather than electrically because, like the fiberglass of the hot stick, the hydraulic fluid is also a good insulator. The hydraulic power is commonly supplied from the bucket truck (cherry picker
Cherry picker
A cherry picker , is a type of aerial work platform that consists of a platform or bucket at the end of a hydraulic lifting system.- Design :...
or aerial work platform
Aerial work platform
An aerial work platform, also known as an aerial device or elevating work platform, is a mechanical device used to provide temporary access for people or equipment to inaccessible areas, usually at height...
) supporting the workers.
The hot stick not only electrically insulates the worker from the energized conductor, it provides physical separation from the device being operated, to reduce the chances of burns which might result from electrical arcing
Electric arc
An electric arc is an electrical breakdown of a gas which produces an ongoing plasma discharge, resulting from a current flowing through normally nonconductive media such as air. A synonym is arc discharge. An arc discharge is characterized by a lower voltage than a glow discharge, and relies on...
if there is a malfunction of the device being operated.
In the United States, ASTM Standard F 711 specifies the stringent requirements for hot sticks, and U.S. OSHA
Occupational Safety and Health Administration
The United States Occupational Safety and Health Administration is an agency of the United States Department of Labor. It was created by Congress of the United States under the Occupational Safety and Health Act, signed by President Richard M. Nixon, on December 29, 1970...
standards require that they be inspected and electrically tested every two years.