ELECTRIC CABLES HANDBOOK
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ELECTRIC CABLES HANDBOOK
The Electricity in Our Life
Early man relied on fire for the luxuries of light, heat, and cooking. Today, we take all these luxuries for
granted. At the flick of a switch, a push of a button, or the turn of a knob, we can have instant power.
Electricity plays a huge part in our everyday lives. Whether it is at home, school, the local shopping
center, or our workplace, our daily routines rely heavily on the use of electricity.
Electricity not only plays a big part in our daily lives at home, but it is extremely important for all the
things that go on in the world around us in our modern life, such as industry that we depend on and
communication as in the form of radio, television, email, the Internet, etc. Transport is another aspect of
our daily life that depends on electricity to some degree.
Since it was invented, most inventions were based off it and it was used to help create the invention.
It adds light to the world and is part of the solution to most modern problems. ... Electricity to this day is
the most important invention because it serves as the baseline for all inventions to come.
Electricity is a convenient energy source because it is easily transmitted over distance via electricity
cables, and has a wide variety of uses. However, electricity is not a primary energy source – it must be
generated before it can be used, whether using coal, oil, natural gas or other fuels. Once it has been
generated, the electricity goes to transformers to make it the correct voltage and then is supplied to
homes and businesses through a network of cables and pylons.
How is electricity generated?
Generators transfer kinetic energy into electrical energy. This can be done in one of two ways:
•
•
Directly – when a turbine (for example wind, hydroelectric of tidal turbines) turns the generator,
producing electricity.
Indirectly – when fuels (e.g. fossil fuels – coal, oil or natural gas) are used to boil water to make
steam which pushes the blades of a turbine, turning the generator. In the case of power stations
which generate electricity in this way, energy is lost to the environment in every stage of the
process, meaning only a third of the energy stored in the fuel is converted into electrical energy.
How is electricity transmitted?
The electricity is sent across the country to homes and businesses through the National Grid.
The National Grid transmits electricity at low current to reduce energy lost as heat while it is being
transferred across cables.
Power stations produce electricity at 13.8 KV. Electricity is sent through the National Grid at 380 KV,
220 KV, or 132 KV, 110 KV. Step-up transformers at power stations produce the very high voltages
needed to transmit electricity through the National Grid’s power lines. But because high voltages are too
dangerous for use in the home, step-down transformers are then used locally to reduce the voltage to
safe levels.
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ELECTRIC CABLES HANDBOOK
INTRODUCTION
Power cables are a major factor in Technological Progress of Industry, Agriculture, Urban and Health
affairs in the world, to meet the needs of each area to achieve the progress and welfare of humanbeings.
The Most Important Usage of Electricity:
1. Heavy engineering industries.
2. Submarines, and ship wiring.
3. Petrochemical industries.
4. Medical appliances.
5. Food industries.
6. Agriculture and Rural areas.
7. Water Desalination plants.
8. Airports, Roads and Lighting the streets.
9. Utilities (houses, schools, hospitals, markets and commercial complexes).
Generating Stations
They are part of the production of electrical power, where Generator converts kinetic mechanical energy
into electrical energy.
The generator takes the rotational kinetic energy of the turbine engine (Prime Mover primary) and
converts the primary energy into Electric energy. The turbine may be steam or gas or hydraulic one.
Generators are three phase parallel connected, and economically we usually generate voltage 13.8 kV,
and are redoubling power produced (13.8 kV) to 220 kV and 380 kV, or greater (in some countries up to
750 kV) by using step-up Power Transformers.
Track of Power from Power Stations to Consumer
TRANSMISSION
Generating Station
•
•
•
3
Generates voltage
13.8 kV.
Generated voltage is
transferred via bus bars
to the transformers to
generate EHV 380 kV,
220 kV.
EHV is connected to the
Primary transmission
stations via Overhead
Transmission Lines.
Primary Transmission
• Receives the EHV, and reduce it
to HV 132, 110 through stepdown transformers.
Secondary Transmission
• HV is reduced by step-down
transformers to MV 33 or
22 KV, and transmit it to major
users and Primary Distribution
substations.
DISTRIBUTION
Primary Distribution
• Receives MV 33 or 22 kV, and
decrease it to 13.8 kV by
transformer.
• Distribute part of the 13.8 KV
to main users, and forward
other part to Secondary
Distribution Station.
Secondary Distribution :
• Reduce the 13.8 kV to 400
volts, and 220 volts 110 volts.
• Distribute 220 & 110 volts to
neighborhoods and rural areas
ELECTRIC CABLES HANDBOOK
Generation of Electric Power:
Power can be produced from one of the following sources:
1- Thermal power stations – diesel power stations (Coal, Oil).
2- Hydroelectric power stations (Water).
3- Nuclear power stations (Atomic energy).
Transmission of Electric Power:
There are two main systems that can transmit electric energy:
1- D.C (direct current) system.
2- A.C (alternating current) system.
Advantages of D.C system:
1- Only two conductors are used for transmission instead of three.
2- Voltage stress on the insulation of cable in D.C system is approximately 70 % of that in
A.C effective voltage having the same value.
3- Inductance, capacitance, phase displacement and other problems are eliminated in D.C
System.
4- No need for stabilizers when used for long distances.
Advantages of A.C system:
1- It is possible to generate medium voltages as 33 kV comparing to 11 kV in D.C system.
2- Alternating voltage can be stepped up or down easily using specified transformers which
is impossible in D.C system.
3- Maintenance of A.C power station is easier and cheaper.
Types of transmission lines:
1- Underground.
2- Overhead.
Advantages of underground system:
1- It can be used in over populated areas.
2- It is subjected to fewer faults compared to overhead system.
3- Maintenance cost is less.
Advantages of overhead system:
1- It is cheaper than underground system.
2- It can be easily repaired (but it takes longer time) and maintained.
3- Insulation difficulties for high voltage cables are not existing in overhead lines.
Effects of Electricity:
1- Thermal Effect:
- Current passing in a conductor is causing some heat.
- In some cases heat is not desired, e.g. lighting purposes where light is required more than heat.
- In other cases heat is required, as in heaters, toasters, etc.
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ELECTRIC CABLES HANDBOOK
2- Chemical Effect:
- It is required in some purposes, as electroplating, charging of batteries and electrolytic refinery of
metals.
- In dry cell batteries the reverse can be seen as the chemical action produces an electric current.
3- Magnetic Effect:
- A magnetic field will surround the when current passes through it.
- If we wrap a wire several times around a piece of soft iron, and allowing a current to pass through
the wire, the soft iron will become magnetic. If we stop the current, the iron will be nonmagnetic
again.
- This magnetic effect causes motors to run, bells to ring, telephones and speakers to operate.
Outline of the Generation, Transport and Distribution of electric energy
Electrical energy, after being produced at generating stations (TPS, HPS, NPS, etc.) is transmitted to the
consumers for utilization. This is due to the fact that generating stations are usually situated away from
the load centers. The network that transmits and delivers power from the producers to the consumers is
called the transmission system. This energy can be transmitted in AC or DC form. Traditionally, AC
has been used for years now, but HVDC (High Voltage DC) is rapidly gaining popularity.
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ELECTRIC CABLES HANDBOOK
Energy Resources
Non-Renewable Energy:
* Energy of coal (used in power plants steam or thermal)
* Energy of oil (used in power plants operated by diesel units)
* Energy of gas (used in gas power plants)
Renewable Energies:
* Energy of rush water using dams (Hydro turbines and generators)
* Wind, Solar, Gas, Hot water tanks underground, Tidal power at sea.
* Nuclear energy (used in nuclear power plants)
Types of Power Plants
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ELECTRIC CABLES HANDBOOK
Generating Electric Power from Non-Renewable Energies
Thermal Power Plant
Thermal stations are generating steam from the boiler where water is heated by coal or oil, and the
generated steam rotates steam turbine, which runs generators for electric power generation.
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ELECTRIC CABLES HANDBOOK
Gas Power Plant
This plant is utilizing the combustion of natural gas (internal combustion units consisting of compressor
and combustion chamber) where Hot gases move through a multistage gas Turbine rotates the gas
Turbine. The shaft of the gas turbine is coupled to Generator to generate electricity.
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ELECTRIC CABLES HANDBOOK
Diesel Power Plant
This plant is utilizing the combustion of diesel fuel (internal combustion units consisting of compressor
and combustion chamber) to generate mechanical energy and run the turbine, which in turn run
generators for electric power generation
Diesel Power Station
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ELECTRIC CABLES HANDBOOK
Combined Cycle Plant
It is utilizing steam and gas (boiler is heated by diesel fuel combustion product, where;
1- Combustion gas runs a gas turbine, which runs a generator for electric power generation.
2- Combustion gas heats a boiler to generate steam, which runs a steam turbine, which runs a generator
for electric power generation.
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ELECTRIC CABLES HANDBOOK
Electric Power Generation from New & Renewable Energy (Green
Energy)
Hydroelectric Power Station
•
It converts the kinetic energy of water flow into electrical energy via water falling into traffic
Lanes in the dam, and down to turbines which runs generators to generate Electric Power.
•
This energy represents 15% of the amount of electricity produced in the world.
Section in a Turbine & Generator, Turbo-Generator
A turbo generator is a turbine connected
to a generator, which together transform
the mechanical energy of a moving fluid,
such as liquid water, steam, natural gas or
air, into electricity. Turbines harness a
system of blades to spin and, via a shaft,
drive the generator.
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ELECTRIC CABLES HANDBOOK
SOLAR ENERGY TO ELECTRIC ENERGY
12
•
Concentrated sunlight on thousands of mirrors, reflected to the receiver (1) on the top of the
central tower.
•
The receiver (1) collects the heat from the Sun and concentrate it to the brine tank (2) contains
Salty Liquid.
•
Brine tank absorbs the heat.
•
The brine heat heats the boiler (2) to produce steam.
•
Steam runs conventional steam turbines (3).
•
The turbine is running the electric generators (4) to generate Electricity.
•
Boiler condensate is collected in reservoir tank (5), and go back to brine tank again.
ELECTRIC CABLES HANDBOOK
Wind Power Station
• Wind rotates the blades (top of the tower), which rotate a shaft coupled to gear-box & connected to run
an electric generator.
• Generator generates electricity which is transmitted to transformer at base of the tower.
Rotor Blade
Nacelle
Hub
Tower
Low speed
shaft
Rotor Hub
High speed
shaft
Gear-box
Transformer
Brake
Brake
Generator
Tidal Power Stations
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•
The sea water rises in some hours of the day up and down as a result of approaching or
distancing the Moon on the coast.
•
Tidal barrages are low-walled dams, usually installed at tidal inlets or estuaries. ... During an
incoming high tide, water flows over the turbines as the water rises. Then, the water flows back
through the turbines as it becomes low tide. The turbines are connected to a generator which
produces the electricity.
ELECTRIC CABLES HANDBOOK
Geothermal Power Plant
Some water in underground is very hot by its nature which are flushed to a steam separator vents which
forward the steam in tubes to the steam turbine causing the central axis of the turbine to rotate, where
the turbine runs the electric generator.
Turbine outlet steam is cooled to be in water form, and water then returns to underground again.
Nuclear Power Station
The nuclear reactor converts nuclear energy into thermal energy to heat boilers, which generate steam
to run the steam turbine, which will run the electricity generator.
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ELECTRIC CABLES HANDBOOK
POWER CABLES CONSTRUCTION
Cables consist of three major components: conductors, insulation, and protective jacket. They come
in a variety of sizes, materials, and types, each particularly adapted to its uses.
The makeup of individual cables varies according to the application. The construction and material are
determined by three main factors:
•
•
•
Working voltage, determining the thickness of the insulation;
Current-carrying capacity, determining the cross-sectional size of the conductor(s);
Environmental conditions such as temperature, water, chemical or sunlight exposure, and
mechanical impact, determining the form and composition of the outer cable jacket.
Cables for direct burial or for exposed installations may also include metal armor in the form of wires
spiraled around the cable, or a corrugated tape wrapped around it. The armor may be made of steel or
aluminum, and although connected to earth ground is not intended to carry current during normal
operation. Electrical power cables are sometimes installed in raceways, including electrical conduit and
cable trays, which may contain one or more conductors. When it is intended to be used inside a building,
nonmetallic sheathed building cable consists of two or more wire conductors (plus a grounding
conductor) enclosed inside a thermoplastic insulation sheath that is heat-resistant.
It has advantages over armored building cable because it's lighter, easier to handle, and its sheathing is
easier to work with.
Power cables use stranded copper or aluminum conductors, although small power cables may use solid
conductors.
The cable may include uninsulated conductors used for the circuit neutral or for ground (earth)
connection. The grounding conductor connects the equipment's enclosure/chassis to ground for
protection from electric shock. These uninsulated versions are known as bare conductors or tinned bare
conductors. The overall assembly may be round or flat. Non-conducting filler strands may be added to
the assembly to maintain its shape. Filler materials can be made in non-hydroscopic versions if required
for the application.
Special purpose power cables for overhead applications are often bound to a high strength alloy, ACSR,
or Alumoweld messenger. This cable is called aerial cable or pre-assembled aerial cable.
Material specification for the cable's jacket will often consider resistance to water, oil, sunlight,
underground conditions, chemical vapors, impact, fire, or high temperatures.
In nuclear industry applications the cable may have special requirements for ionizing radiation
resistance. Cable materials for a transit application may be specified not to produce large amounts of
smoke if burned (low smoke zero halogen).
Cables intended for direct burial must consider damage from backfill or dig-ins. HDPE jacket is common
for this use. Cables intended for subway (underground vaults) may consider oil, fire resistance, or low
smoke as a priority.
Few cables these days still employ an overall lead sheath. Transmission or submarine cables are more
likely to use lead sheaths. However, lead is in decline and few manufacturers exist today to produce
such items. When cables must run where exposed to mechanical damage (industrial sites), they may be
protected with flexible steel tape or wire armor, which may also be covered by a water-resistant jacket.
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ELECTRIC CABLES HANDBOOK
CLASSIFICTION OF POWER CABLES
Classification of Cables by Conductor Types
1-Copper Conductors
Annealed Copper Conductors
Tinned Copper Conductors
Hard Drawn Copper Conductors
2-Aluminum Conductors
AAC All Aluminum Conductor
ACSR Aluminum Conductor Steel Reinforced
AAAC All Aluminum Alloy Conductor
ACAR Aluminum Conductor Aluminum Alloy Reinforced
Classification of Cables by Insulation Type
The cables also are called by type of material used for insulation in the
cable industry and is the most important second component in cable.
PVC Poly-vinyl Chloride
XLPE Cross-Linked Polyethylene
PE Polyethylene
EPR Ethylene Propylene Rubber
Si R Silicon Rubber
Classification of Cables by Rated Voltage
➢ Low Voltage up to 1000 V
➢ Medium Voltage from 3.6 KV to 35 KV
➢ High Voltage from 45 KV to 150 KV
➢ Extra High Voltage above 150 KV to 500 KV
➢ Rated Voltage Parameters
Uo Voltage between phase and ground
U Voltage between phase and phase
Um Max. Rated Voltage
➢ Rated Voltage: is normally defined as: U / Uo (Um)
Ex. 0.6 / 1 (1.2) KV, 6 / 10 (12) KV, 76 / 132 (145) KV, etc.
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ELECTRIC CABLES HANDBOOK
MATERIALS USED IN POWER CABLES MANUFACTURING
CONDUCTOR MATERIALS:
1-Copper
➢ About 98% of all copper is used as metal, taking advantage of distinctive physical properties being malleable, ductile, with good conductivity of both heat and electricity, and being resistant to
corrosion.
➢ The purity of copper is expressed as 4N for 99.99% pure or 7N for 99.99999% pure. The numeral
gives the number of nines after the decimal point when expressed as a decimal (e.g. 4N means
0.9999, or 99.99%).
➢ Copper resistivity is determined as 17.241 Ω.mm2/km at the temperature of 20 °C, equivalent to
conductivity of 100% as defined in International Electro-technical Commission IEC.
➢ Copper conductors should be Annealed so don't be with severe hardness, and with sufficient
flexibility to curvatures during manufacturing and lapping on rollers, or during installation and
connection.
Copper With Tin Coating
➢ Conductors dipped in tin are more resistant to water, have increased conductivity and allow for easy
soldering.
➢ Tinned Copper protects from erosion in applications exposed to extreme temperatures.
Tinned copper can be exposed to temperatures up to 150 degrees Celsius.
2- Aluminum
➢ It has a low density and high conductivity, so it can transport current with minimal losses, while
also being light enough to not need large support structures. However,
pure Aluminum (used in overhead cables) is not very strong so these cables are reinforced with
steel core.
➢ Aluminum resistivity is determined as 28.26 Ω.mm2/km at the temperature of 20 °C, equivalent to
conductivity of 61% (compared with copper) as defined in International Electro-technical
Commission IEC.
➢ Purity of Alum should be at least 99.5%.
➢ Types of EC Aluminum:
1. H12: 50% Hard
2. H14: 75% Hard
3. Alloy: 100% Hard
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ELECTRIC CABLES HANDBOOK
Material properties of pure Copper and Aluminum
Characteristic Ratios between Copper and Aluminum
3- Copper-Clad-Aluminum Conductors
➢ The core is of Aluminum with a thin layer of Copper on outer surface.
➢ The main purpose of the copper plating is to get use of the function that current is flowing on outer
surface of conductor, and get less conductor mass.
➢ Its conductivity still 61% of that for copper.
COPPER
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ALUMINUM
COPPER CLAD ALUMINUM
ELECTRIC CABLES HANDBOOK
Comparison between Copper and Aluminum
ITEM
Unit
COPPER
ALUMINUM
Purity
Melting Point
0
Density at 20 C
Resistivity
Conductivity
U.T.S
Magnetism
Corrosion Effect
Usage
Advantages
%
Deg. C
gm / cc
99.98
1083
8.89
99.50
660
2.703
Ω.mm2 / km
Siemens
kg / mm2
17.241
58
40
Anti-magnetic
Coated with Green layer
Conductors- Screens- Lugs
18.26
35
15
Anti-magnetic
Coated with AL Oxide
Conductors- Screens- Lugs
High Conductivity
Medium Conductivity
High Tensile Strength
Heavy weight
Expensive
Light weight
Fast oxidation
Resistance = 1.5 that of CU
Disadvantages
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ELECTRIC CABLES HANDBOOK
INSULATION & SHEATHING MATERIALS:
POLYMERIC MATERIALS:
➢ Polymeric materials are extracted from the petrochemical industries.
➢ The name polymer is used for different types of resins, and synthetic rubber.
Plastic polymers are divided into two main types:
A- Thermo-plastics
Thermoplastics are types of plastics soften with heat, and solidify when cold.
B- Thermo-sets
Thermosets are materials solidify more when heated, till its degradation state.
In industrial we can convert many thermoplastics to thermosets by a using a special treatment and
With the help of cross-linking agent called catalyst.
Thermoplastics used in the cable industry:
1- Polyvinyl-chloride-PVC
2- Low Density Polyethylene LDPE, Linear Low Density Polyethylene LLDPE
3- Medium Density Polyethylene MDPE
3-High Density Polyethylene HDPE
4- Polypropylene – PP
5- Rubber
6- Nylon is thermoplastic but very tough material.
Thermosets used in the cable industry:
1- Silicone Rubber SR, and Butyl Rubber
2- Ethylene Propylene Rubber EPR
3- Cross-linked Polyethylene XLPE
Disadvantages of Polymeric Materials:
1. Low resistance to partial discharge, as this phenomenon leads to the decomposition of the
insulation, and results in cable failure.
2. Low resistance to water or moisture ingress.
3. It can contain voids and other impurities during its manufacturing.
Properties to be Considered in Insulation Materials
➢ High dielectric strength
➢ High insulation resistance
➢ Effective Thermal Resistance
➢ Non-hygroscopic
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ELECTRIC CABLES HANDBOOK
COMPARISON BETWEEN SOME TYPES OF INSULATION & SHEATHING MATERIALS
Properties
Unit
XLPE
PE
PVC
Si R
Max. operating temperature
o
90
70
70
180
Max. short circuit temperature
o
C
250
160
160
***
N / mm2
Min. 12.5
Min. 12.5
Min. 12.5
Min. 4.2
%
Min. 200
Min. 120
Min. 120
Min. 200
Excellent
Excellent
Excellent
Excellent
C
Mechanical Properties:
* tensile strength
* elongation at break
Physiochemical Properties:
•
resistance to acids
•
resistance to alkaline
“
“
“
“
•
resistance to oil
“
“
“
Good
•
resistance to heat distortions
“
Fair
Fair
Excellent
Ohm.cm
Min 1016
Min 1013
Min 1013
Min 1015
X 10-4
Max 40
Max 10
Max1000
Max 200
6–8
****
36.7
3.67
Electrical Properties:
•
volume resistivity
•
dielectric power factor
•
dielectric constant
•
insulation resistance
2.3 – 2.3
M W .km
3.67
****
constant
Poly Vinyl Chloride PVC
PVC is a polymer of the monomer vinyl chloride.
Vinyl chloride (H2C=CHCl) is made up of hydrogen, carbon and chlorine.
As a polymer, it is a repetition of monomer units.
Vinyl Chloride Manufacturing
It is a reaction of hydrogen chloride with Acetylene, where reaction happens in gaseous state. Mercury
chloride is utilized as an agent. Vinyl chloride is used for producing Polyvinyl Chloride.
= (C2H3Cl)n
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ELECTRIC CABLES HANDBOOK
In general for PVC material, it is mainly composed of 5 main components:
1- PVC RESIN K value (e.g. K70), where K is a value related to Molecular Weight of PVC, and
the Viscosity. If K is high, viscosity will be high, and vice versa.
2- PLASTICIZER:
The plasticizers are organic substances with various characteristics, whose main function is to
intercalate the rigid polymer structures of material such as PVC for an easy movement and flexibility,
making them more precisely "plastics." The presence of plasticizers in the PVC structure will influence
different
3- FILLER
Fillers like Calcium Carbonate are added to a polymer formulation to reduce the costs and improve
the properties. Fillers can be either solid, liquid or gas. They occupy space and replace the expensive
resin with less expensive compounds without modifying other characteristics.
4- STABILIZER
Stabilizers allow plastic items to be produced faster and with fewer defects, extend their useful
lifespan, and facilitate their recycling. ... Even for objects made from the same type of plastic, different
applications may have different stabilization requirements.
5- LUBRICANT
A lubricant is a substance, usually organic, introduced to reduce friction between surfaces in mutual
contact, which ultimately reduces the heat generated when the surfaces move. It may also have
the function of transmitting forces, transporting foreign particles, or heating or cooling the surfaces.
And depending on mixing ratio of these components, we get different types of PVC material with
different properties, where the most influential components on the properties are:
1- Resin type
2- Filler type
3- Plasticizer type
Testing of PVC material
1- Density measure.
2- Tension Elongation test (as a measure for its Flexibility, and its Melt Flow Index “MFI”
POLYETHYLENE PE
It is a polymer formed from Long Chains of Ethylene Monomer.
Ethylene Molecule: CH2 = C2H4, where it is Two molecules with double bond.
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ELECTRIC CABLES HANDBOOK
Many kinds of polyethylene are known, with most having the chemical formula (C2H4)n. PE is usually a
mixture of similar polymers of ethylene, with various values of n. It can be low density or medium density
or high density. Polyethylene (PE) is a thermoplastic polymer consisting of long chains produced by
combining the ingredient monomer ethylene. It has good electrical properties. In terms of flexibility,
polyethylene can be rated stiff and hard, depending on molecular weight and density. Moisture
resistance is rated excellent. Specially formulated Black is excellent weather resistance.
LDPE
Low Density Polyethylene has a high degree of short and long chain branching, which means that the
chains do not pack into the crystal structure as well. It has, therefore, less strong intermolecular forces
as the instantaneous-dipole induced-dipole attraction is less. This results in a lower tensile strength and
increased ductility. LDPE is created by free radical polymerization. The high degree of branching with
long chains gives molten LDPE unique and desirable flow properties.
HDPE
High Density Polyethylene has a low degree of branching and thus stronger intermolecular forces and
tensile strength. The lack of branching is ensured by an appropriate choice of catalyst (for example,
chromium catalysts or Ziegler-Natta catalysts) and reaction conditions. It is generally used as a
sheathing material where it provides high resistance to water penetration, is very hard, has low
coefficient of friction, and is abrasion resistant.
CROSS-LINKED POLYETHYLENE XLPE
It is a medium to high density Polyethylene contains its polymeric chain a Linking Bonds, making them
more durable and those also are made of high-density polyethylene.
XLPE contains cross-linking bonds in the polymer structure, whereby itself contribute in the x-linking of
polyethylene particles when exposed to conditions that Work on x-linking by one of the assigned
methods, and polyethylene changes from Thermoplastic status changes to Thermoset.
CROSS- LINKING AGENTS
Organic Peroxide:
➢ A chemical compound containing a high proportion of Oxygen, and mixed with Polyethylene.
➢ Polyethylene containing an organic peroxide is crosslinking at high temperatures, and high
pressures, and it is done on CV line.
➢ High temperature works on decomposition of peroxide, while high pressure works to prevent
stagnation of byproduct gasses which can form bubbles appearing in the Insulation.
➢ The insulation temperature at extruder outlet should be not less than 130 ° C to prevent the
primary x-linking in the X-head.
Electron Beam:
➢ In E-Beam Irradiation, the polymer is exposed to an energetic, highly charged stream of electrons.
➢ The high velocity electrons create a free radicals (molecules that contains at least one unpaired
electron) in the polymeric insulation.
➢ The free radicals react with each other and form a double bond which leads to cross-linking of PE
molecules.
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ELECTRIC CABLES HANDBOOK
Two Steps Silane / Sioplas Method
➢ In this case, the PE is mixed with Catalyst during extrusion, and the PE X-linking is achieved with
presence of Moisture (water vapor or water) and Heat.
➢ This method has been developed by DOW CORNING, and is known as Sioplas.
Grafting of Vinylsilanes onto Polyethylene
Moisture Effect on X-linking of Silane-Grafted
Polyethylene
Heat Effect on X-linking of Silane-Grafted Polyethylene
Hydrolysis
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ELECTRIC CABLES HANDBOOK
Polyamide (Nylon)
Nylon is a generic designation for a family of synthetic polymers known generically as polyamides. It
has good durability, high elongation, excellent abrasion resistance and high resilient. It also resists
insects, fungi, molds, rot and many chemicals.
Polypropylene
Polypropylene (PP), also known as polypropene, is normally tough and flexible, especially when
copolymerized with ethylene. It is similar as polyethylene in electrical properties. This material is
primarily used as an insulation material. Typically, it is harder than polyethylene. This makes it
suitable for thin wall insulations.
Polyurethane
Polyurethane (PUR and PU) combines the best properties of both rubber and plastic. This material is
used primarily as a cable jacket material. It has excellent oxidation, oil, and ozone resistance. Some
formations also have good flame resistance. It is a hard material with excellent abrasion resistance.
TPE
Thermoplastic Elastomer. TPE is cross linkable elastomers with styrene rubbers which gives
homogenous compound excellent hybrid properties with rubbery effect. TPE gives advantage to cost
effective and achieves high performance applications and specification to thermoset rubbers. TPE is
normally tough, cut resistant, flexible, and smooth, with vibrant coloring.
Flame Retardant Materials
Fire retardant materials are designed for use in fire situations where the spread of flames along a cable
route needs to be retarded.
Due to relative low cost, fire retardant cables are widely used as fire survival cables.
No matter the cables are installed in single wire or in bundles, during a fire, the flame spread will be
retarded and the fire will be confined to a small area, thus reducing the fire hazard.
Low Smoke & Halogen Free & Fire retardant (LSZH)
Low smoke zero halogen or low smoke free of halogen is composed of thermoplastic or thermoset
compounds that emit limited smoke and no halogen when exposed to high sources of heat, e.g.
flame. In a fire, a halogen-containing plastic material releases, e.g. hydrogen chloride, a poisonous gas
that forms hydrochloric acid when it comes in contact with water. Designated Halogen-free cables,
on the other hand, do not produce a dangerous gas/acid combination or toxic smoke when exposed to
flame. Low smoke zero halogen cable reduces the amount of toxic and corrosive gas emitted during
combustion. This type of material is typically used in poorly ventilated areas such as aircraft or rail
cars. Low smoke zero halogen is becoming very popular and, in some cases, a requirement where
the protection of people and equipment from toxic and corrosive gas is critical. It is often lighter, so
overall cable network system weights can be reduced. The environmental impact of halogen free
cabling can be lower if there are fewer toxic chemicals.
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ELECTRIC CABLES HANDBOOK
HFFR (Low smoke, Flame retardant, Halogen-free and Thermoplastic compounds)
When PVC is not acceptable due to the problems chlorine (halogen) containing materials present in
the event of a fire HFFR must be used. (In accordance with IEC 60092-359 type SHF1). The
materials will not propagate a fire along a cable run, drip or give off black smoke. No acid gases will
be released during a fire that can corrode and damage expensive equipment.
CPE
Chlorinated Polyethylene. An oil, ozone and heat resistant sheathing compound.
Rubber
Rubber normally includes natural rubber and SBR compounds. Natural rubber is an elastomer (an
elastic hydrocarbon polymer) that was originally derived from latex, a milky colloid produced by
some plants. It is normally very stretchy and flexible and extremely waterproof. Rubber exhibits unique
physical and chemical properties. Rubber’s stress- strain behavior exhibits the Mullins effect, the
Payne effect, and is often modeled as hyperelastic. Owing to the presence of a double bond in each
repeat unit, natural rubber is sensitive to ozone cracking.
Styrene- butadiene rubber (SBR)
It is a synthetic rubber consisting of styrene and butadiene. It has good abrasion resistance and good
aging stability when protected by additives. It offers good durability, less shrinkage and flexibility, as
well as being resistant to emulsification in damp conditions.
Synthetic Rubber
Synthetic rubber is any type of artificial elastomer, invariably a polymer. An elastomer is a material with
the mechanical (or material) property that it can undergo much more elastic deformation under stress
than most materials and still return to its previous size without permanent deformation. Synthetic
rubber serves as a substitute for natural rubber in many cases, especially when improved material
properties are required.
Silicon Rubber
Silicone rubber is an elastomer (rubber-like material) composed of silicone—itself a polymer—
containing silicon together with carbon, hydrogen, and oxygen. Silicone rubber offers good resistance to
extreme temperatures, being able to operate normally from −55 °C to +300 °C. At the extreme
temperatures, the tensile strength, elongation, tear strength and compression set can be far superior to
conventional rubbers although still low relative to other materials. Organic rubber has a carbon to
carbon backbone which can leave them susceptible to ozone, UV, heat and other ageing factors that
silicone rubber can withstand well. This makes it one of the elastomers of choice in many extreme
environments. Compared to organic rubbers, however, silicone rubber has a very low tensile strength.
For this reason, care is needed in designing products to withstand even low imposed loads. The
material is also very sensitive to fatigue from cyclic loading. Silicone rubber is a highly inert material and
does not react with most chemicals.
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ELECTRIC CABLES HANDBOOK
Nitrile Butadiene Rubber (NBR)
Nitrile butadiene rubber (NBR) is a family of unsaturated copolymers of 2-propenenitrile and
various butadiene monomers (1,2-butadiene and 1,3-butadiene). Although its physical and
chemical properties vary depending on the polymer’s composition of nitrile, this form of synthetic
rubber is generally resistant to oil, fuel, and other chemicals (the more nitrile within the polymer, the
higher the resistance to oils but the lower the flexibility of the material).
NBR/PVC
NBR/PVC is admixture of NBR and PVC. It unite both advantages of those two materials. It has
better ability to resist oil, chemicals, ozone and weather.
Polybutadiene
Polybutadiene is a highly resilient synthetic rubber. Heat buildup is lower in polybutadiene rubber
based products subjected to repeat flexing during service. It is sensitive to oxidation and ozone
owing to the reactivity of the double bond present in every repeat unit. Anti-oxidants are normally
added to protect against cracking and deterioration.
EPR
Ethylene Propylene Rubber. A water and ozone resistant, flexile, cross linked high grade insulation
material. However, relatively poor cold traction and cut growth resistance limits the use to blends with
other types of rubber.
EVA (Flame retardant halogen-free thermoset compound)
EVA, ethylene vinyl acetate, is a multi-functional elastomer, which resists the combined deteriorating
influences of heat, oil and weather. (In accordance with IEC 60092-359 type SHF2). For offshore
applications, EVA can be compounded to produce high quality cable sheathing with low smoke and
flame propagation, and with no emission of halogenous acids.
It is a polymer that approaches elastomeric materials in softness and flexibility, it can be processed like
other thermoplastics. The material has good clarity and gloss, barrier properties, low-temperature
toughness, stress-crack resistance, hot-melt adhesive water proof properties, and resistance to UV
radiation. EVA has little or no odor and is competitive with rubber and vinyl products in many electrical
applications.
Neoprene (Polychloroprene)
Neoprene in general has good chemical stability, and maintains flexibility over a wide temperature
range. It is both oil-resistant and sunlight-resistant, making it ideal for many outdoor applications. The
most stable colors are Black, Dark Brown, and Gray. The electrical properties are not as good as other
insulation materials.
CSPE (CSM)
Chloro-sulphonated Polyethylene. Oil, ozone and heat resistant sheathing material.
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ELECTRIC CABLES HANDBOOK
EPDM
EPDM (ethylene-propylene-diene elastomer), is a hydrocarbon rubber that combines electrical
performance suitable for fire resistant offshore cables with mechanical toughness and resistance to
ozone, UV light and heat. Its wet electrical properties are unique. It is very flexible at high and low
temperatures (-55°C to 150°C). It has good insulation resistance and dielectric strength, as well as
excellent abrasion resistance. EPDM also has better cut-through resistance than Silicone rubber, which
it replaces in some applications.
EPDM exhibits satisfactory compatibility with fireproof hydraulic fluids, ketones, hot and cold water, and
alkalis, and unsatisfactory compatibility with most oils, gasoline, kerosene, aromatic and aliphatic
hydrocarbons, halogenated solvents, and concentrated acids.
PVDF
Polyvinylidene fluoride, or polyvinylidene difluoride (PVDF) is a highly non-reactive and pure
thermoplastic fluoropolymer. PVDF is a specialty plastic material in the fluoropolymer family; it is
used generally in applications requiring the highest purity, strength, and resistance to solvents,
acids, bases and heat and low smoke generation during a fire event. Compared to other
fluoropolymers, it has an easier melt process because of its relatively low melting point of around 177
°C. It has a low density (1.78) and low cost compared to the other fluoropolymers.
Polytetrafluoroethylene PTFE
It is a synthetic fluoropolymer of tetrafluoroethylene. The most well-known brand name of PTFE is
Teflon. PTFE is a fluorocarbon solid, as it is a high-molecular-weight compound consisting wholly of
carbon and fluorine. It is hydrophobic. PTFE has one of the lowest coefficients of friction against any
solid.
PTFE has excellent dielectric properties. Combined with its high melting temperature, this makes it the
material of choice as a high-performance substitute for the weaker and lower melting point polyethylene
that is commonly used in low-cost applications. This material has excellent temperature range and
chemical resistance. It is not suitable where subjected to nuclear radiation and does not have good high
voltage characteristics.
PFA
Perfluoroalkoxy (PFA) is very similar in composition to the fluoropolymers PTFE and FEP
(fluorinated ethylene-propylene). PFA and FEP both share PTFE’s useful properties of low
coefficient of friction and non-reactivity, but are more easily formable. PFA is similar to FEP in
terms of its mechanical properties. These two are both superior to PTFE with regards to their
flexibility. However, their ability to endure repetitive folding (flex life) is actually lower than PTFE. PFA
has a higher flex life than FEP. PFA is preferable to FEP where heat is concerned, but PTFE itself is
slightly more resistant to heat than both. PFA is more affected by water absorption and weathering
than FEP, but is superior in terms of salt spray resistance.
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ELECTRIC CABLES HANDBOOK
FEP
In terms of corrosion resistance, Fluorinated ethylene propylene (FEP) is the only other readily
available fluoropolymer that can match PTFE's own resistance to caustic agents, as it is a pure
carbon-fluorine structure and fully. Thermally, FEP stands out from PTFE and PFA by having a
melting point of 260 °C (500 °F), around forty degrees lower than PFA and lower again than PTFE.
Electrically, PTFE, FEP and PFA have identical dielectric constants, but FEP's dielectric strength is
only surpassed by PFA. However, whilst PFA has a similar dissipation factor to PTFE, FEP's
dissipation is around six times that of PFA and EFTE (making it a more non-linear conductor of
electrostatic fields).
TFE
TFE Teflon is extrudable in a hydraulic ram type process. Lengths are limited due to amount of
material in the ram, thickness of the insulation, and preform size. TFE must be extruded over a
silver- or nickel coated wire. The nickel- and silver-coated designs are rated 260°C and 200°C
maximum, respectively. The cost of Teflon is approx. 8 to 10 times more than PVC compounds.
METALLIC SHEATH or METALLIC SCREEN:
Metal sheath is essential in the cables to provide a suitable mechanical protection, also prevents water
entry, as required by the specification (IEC 60502), especially for cables of KV rating above 1 KV.
METALLIC SHEATH MATERIALS
Lead & Lead alloys:
Lead is easy casted, with good resistance to corrosion, but with very low mechanical properties,
so Lead Alloy is casted to improve those characteristics.
Aluminum & Aluminum alloys:
Aluminum is used as metal sheath for cables because it is stronger than Lead due to its high
mechanical strength, it is difficult for cable bending operations.
In addition, its severe mechanical stresses resulting from thermal expansion will affect cable
connections, so this problem was overcome by using sheath of corrugated aluminum.
Copper Screen
A tape of Copper or Copper Wires applied over insulation.
Advantages of Metal Sheath:
1- Keep content of the Electric field within the cable.
2- Providing a path for short circuit to ground.
3- Reduce electrical stresses on insulation, and especially surface stresses that cause cable failure.
4- Reduce noise on communication devices.
5- In the case of electrical shock risk, it acts as good earthing for the cable.
6- Mechanical and chemical protection.
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ELECTRIC CABLES HANDBOOK
ARMORING MATERIALS:
It provides mechanical protection for the cables laid underground against mechanical interpretations
that occur during transportation and installation operations.
MATERIALS USED FOR ARMORING:
1- Galvanized steel tapes
2- Galvanized steel wires
3- Aluminum tapes (for single core cables)
4- Aluminum wires (for single core cables)
5- Mix of Steel Wires and Copper wires (for single core cables)
NOTE:
In some cases, Armoring Layer is used as a pass-way for short circuit current to ground, so its Area &
DCR are considered in cable design.
COMMON MATERIALS FOR OVER SHEATH (OUTER JACKET)
➢ Jute sulfonated bitumen, for Submarine cables.
➢ Poly Vinyl chloride, for LV, and MV cables.
➢ Polyethylene (LDPE, MDPE, HDPE), for LV, MV, and HV/EHV cables.
➢ Chloro-sulphonated PE (CSPE), for cables in petrochemical industries, to resist oil, ozone,
climate.
➢ Some materials needed to resist high temperature, resist oil effect, and slow down the flame as
Flame-Retardant, which are as follows:
o Silicon Rubber (resist high temperature).
o Chloroprene Rubber (flexible with high mechanical properties).
o Fluorinated Rubber (resist oils, and withstands high temperature).
o Low Smoke Halogen Free LSHF, LSZH.
o Low Smoke Low Halogen LSLH
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ELECTRIC CABLES HANDBOOK
COPPER ROD CASTING
CASTING SYSTEM:
The raw material for Rod production is Electro-Refined Cathode, which can be directly fed into a
furnace for melting.
A continuous casting system nearly always consists of the following parts:
- Melting furnace
- Holding furnace
- Casting machine
- Cooling system
- Burrs removing installation
- Rolling mill
- Pickling
- Shear
- Coiler
➢ Copper cathodes are melted in a Melting furnace and charged into a holding furnace.
➢ Before the melt enters the casting machine, the oxygen content is measured by an oxycell
system.
➢ The casting machine is of the Hazelett type with two steel belts placed above each other.
➢ The melt is casted between the two conveyer belts and then cooled down.
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ELECTRIC CABLES HANDBOOK
➢ The rectangular bar is rolled in a Krupp rolling mill with 15 passes, where a rod of 8 mm diameter
is formed.
➢ High speed cleaning (Acid Pickling)
- No copper dust
- Bright surface luster
➢ Full line automation Coiler
- Auto weighing of coil
- Compact packing
- Auto coil handling
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ELECTRIC CABLES HANDBOOK
Sl.
33
Material Characteristics
Units
Requirements
1
Density
Kg/m3
8890
2
Outer Diameter
mm
8,0 ± 0.3
3
Conductivity (Min)
M/Ω. mm2
58,6
4
Surface Control
5
Surface Oxides (Max)
A°
1000
6
Tensile Strength (Min)
N/mm2
200
7
Elongation (Min)
%
30
SMOOTH , CLEAN, NO OXIDATION
ELECTRIC CABLES HANDBOOK
PVC COMPOUND MANUFACTURING
Poly Vinyl Chloride (PVC) Formulation
FILLER
RESIN
PLACTISIZER
STABILIZER
LUBRICANT
Produced by free radical polymerization, PVC has the following structure:
[-CH2-CHCl-]n
Where the degree of polymerization, n, ranges from 500 to 3500.
Ingredients Used in PVC Compounding
RESIN
➢PVC resin is available in a wide range of molecular weights. In the United States, the molecular
weight is expressed as inherent viscosity (I.V.); in Europe it is expressed as K value, in Japan it is the
degree of polymerization.
➢Commercial PVC resins available range from an I.V. of 0.50 to 1.15 (K value 47 to 76).
➢The higher the I.V., the higher the molecular weight and the greater the stiffness.
➢I.V. 0.98 -1.16 is normal for Extrusion in wire and cable industry.
STABILIZERS
PVC Heat Stabilizer
The job of the stabilizer is to delay heat degradation, so that the compound can be fabricated before it
degrades.
Main Groups of Heat Stabilizers
➢Lead stabilizers: Sulphate, Phosphate, Stearate
➢Mixed metal stabilizers: Calcium, Barium, Cadmium / Zinc stabilizers
➢Tin stabilizers: Methyl-, Butyl -, Octyl -Tin Mercaptide
➢Organic stabilizers: Organic Phosphates, Epoxy compounds
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ELECTRIC CABLES HANDBOOK
PLASTICIZERS
Plasticizers Additives converting the hard PVC resin into flexible & workable material, and Provide the
resulting compounds with new properties.
Quantity of plasticizer depends on:
The required degree of flexibility (hardness),
The required mechanical properties (Elongation and Tensile strength)
The application temperature (volatility, migration rate)
LUBRICANTS
Lubricants are materials that control the fluxing (melting) point in the extruder/molder to achieve the
best processing characteristics and physical properties.
There are three types of lubricants: external, internal, and external / internal.
External Lubricants–Provide good release from metal surfaces and lubricate between the
individual PVC particles and the metal surface.
As the level of external lubricant is increased, it moves the melting point of the PVC in the
direction of the die.
Internal Lubricants–Provide lubrication at the molecular level between resin particles, and
reduce the melt viscosity.
External/Internal Lubricants–These materials provide both external and internal lubrication
depending on the combination of chemical groups contained.
FILLERS
Calcium carbonate is the mostly used filler with PVC.
It has the ability to increase slightly the impact strength if it has:
* Low particle size (1-2 micron)
* Good surface treatment
As the level of calcium carbonate increases, overall material cost decreases, but the weight per meter
of product increases. This is because the specific gravity of calcium carbonate is higher than the
specific gravity of PVC.
Calcium carbonate in PVC is used to reduce compound cost and weather-ability of compounds.
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ELECTRIC CABLES HANDBOOK
Compounding Plant
High Intensity Mixer
The high impact velocity of the blades and their sheering action lead to:
Break down big particles
Dispersion mixing of the entire mixture.
Allow the additives to melt and penetrate into PVC resin
Evacuate water vapor.
Mixing Procedure
➢Enter resin + solid additives in hot mixer and mix at high speed until reaching 115°C, or until mixer
torque reaches the minimum reading (Dry Powder).
➢The degree of filling for the mixer is form 50-80%.
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ELECTRIC CABLES HANDBOOK
Single Screw (The Kneader)
It has Two movements:
I. Rotating
II. Reciprocating
Melting depend on the shear force Excellent mixing
Changeable elements
-Conveying & mixing sets
-Semi cylindrical elements
Pelletizing extruder
It can be:
- Twin screw extruder: for both compounding & pelletizing
- Two stage extruder:
1st stage: single screw for compounding
2nd stage : single screw for pelletizing
Cutting blades
* Calibration (every start up)
* Sharpening (periodically)
Air or water cooling is essential to avoid pellets sticking.
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ELECTRIC CABLES HANDBOOK
Cooling and classification
It can be:
-Vibrating cooler
-Fluidized bed cooler
Cooling air
-Atmospheric air
-Cold air (cooled by chilled water)
Classifier
-3-4 mm St. St. Screen.
-To catch over size pellets
TYPES OF PVC MANUFACTURED:
PVC INSULATION:
PVC (70 deg. C)
PVC (85 deg. C) FOR SINGLE CORE (Y/G) BS 7655
PVC (FR), IEC 60332
PVC FILLING
PVC SHEATHING:
PVC Standard (70 deg. C)
PVC FRNT (Flame retardant, Natural color)
PVC FRNT-UV
PVC LSLH Low smoke Low Halogen (IEC 61034).
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ELECTRIC CABLES HANDBOOK
Different Types of Wires and Cables
Electrical cable and wires are considered as a same thing. In fact they are quite different. A wire is
made of a single electrical conductor while a cable is a group or bundle of multiple wires inside a
common sheathing. Both of them are used for carrying electrical current.
Nowadays due to the advancement in technology, almost everything is powered by electricity. Be it
indoor or outdoor, we need supply of smooth, uninterrupted electricity which is achieved by using
suitable type of wires and cables. Not only the electrical sector uses cables and wires for power
transmission and distribution to our house and industries, the Telecom sector also relies on various
types of cables for uninterrupted data transmission.
Types of Electric Power Transmission Systems:
There are two main systems that can transmit electric energy:
1- D.C (direct current) system.
2- A.C (alternating current) system.
Types of Electric Power Transmission Cables:
1-Underground Cables
1-1-Single Core Cables
1-2-Multi-core Cables
2-Overhead Transmission Lines
The following table shows a comparison between overhead lines and underground cables as a means
to transfer power, to demonstrate the advantages and disadvantages of each.
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ELECTRIC CABLES HANDBOOK
Types of Cables
Power Cables:
Low Voltage.
Medium Voltage
High Voltage & Extra High Voltage Cables.
Over Head Transmission Lines.
Telecommunication Cables:
Metallic Cables (Telephone cables).
Optical Fiber Cables & FTTH.
Industrial Cables:
Instrumentation Cables.
Control Cables.
Specialty Cables.
Building & Grounding Wires:
Insulated building wires.
Insulated grounding wires.
Insulated flexible wires.
THHN.
Flexible cables.
Cathodic Protection Cables
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ELECTRIC CABLES HANDBOOK
Low Voltage Cables
Low Voltage cables are used to supply power to large motors, industrial equipment, lighting and portable
appliances. Usually used in buildings, factories & electrical distributions.
Residential Area
Compact
substation
Factory
380 V
220V
220V
220V
13.8 KV MV cable
Voltage Grade is (1 KV) for IEC and BS specification.
Low voltage system is:
•
Single core cable (1 phase core).
•
Two cores (1 phase core and 1 grounding core).
•
Three cores cable (3 Phase cores, 2 phases cores with one grounding / neutral, 1 phase core + 1
neutral core + 1 grounding core).
•
Fore cores cable (3 phases cores + 1 neutral / grounding core).
•
Five cores cable (3 phase cores + 1 neutral core + 1 grounding core).
Cable’s components:
•
•
•
•
•
Conductor.
Insulation.
Armor bedding.
Armor.
Outer Jacket.
Power low voltage cables (LV cables) are used for electrical equipment with a voltage rating between
50 to 1000V for alternating current and between 75 and 1500V for direct current, thereby they are not
subjected to high electric stress.
Submarine
Cable
41
Ship Wiring
Cable
Petrochemical
Cable
ELECTRIC CABLES HANDBOOK
1- Sector CU Conductor
2- PVC or XLPE (RED – YELLOW – BLUE – BLACK)
3- Bedding / Inner Covering
4- STA (steel tape armor)
5- PVC Sheath
Medium Voltage Cables
Voltage Grade from 5 KV to 35 KV for IEC and BS specification.
Medium Voltage cables are used in main feeder, distribution and branch circuits in commercial, industrial
and electric utility installations.
Substation – step
down transformers
Compact
substation
Tower
Heavy
Industry
HV Cables
MV Cables
MV Cables
MV Cables
MV cables are defined as single or multi-conductor cable rated for 2001 volts up to 35,000 volts.
Type MV cables are typically specified as either an MV-90 or an MV-105, with the 90 or 105 designating
the maximum conductor temperature in degrees Celsius (ºC).
123456789-
CU / AL Conductor
Semi-Con Conductor Shield
XLPE Insulation
Semi-Con Insulation Shield
CU Tape Screen (or wires)
Yarn Filler / PVC
Bedding / Inner Covering
Steel Wire Armor SWA (or Steel Tape armor)
PVC-ST2
High & Extra High Voltage Cables
For High Voltage cables, the voltage Grade starting from 66 KV to 132 KV according to IEC and ICEA
specification. For Extra High Voltage cables, the voltage Grade starting from 220 KV to 380 KV
according to IEC and ICEA specification.
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ELECTRIC CABLES HANDBOOK
High and Extra high voltage cables mainly used in transmitting the electrical powers from power stations
into sub-stations or from sub-station to another.
Step up
transformer
Power
Plant
Compact
substation
Substation – step
down transformers
LV Cables
MV Cables
13.8 KV MV cable
380 KV / 132 KV HV / Extra HV Cables
These cables are used in transporting electric power voltage of 66 kV up to 500 kV.
These lines are mainly used in the transmission lines between two units of an electricity distribution grid,
a generator unit and a distribution unit or inside a station or sub-station. These insulated cable circuits
may also be used in conjunction with overhead lines.
12345-
CU / AL Conductor
Semi-Con Conductor Shield
XLPE Insulation
Semi-Con Insulation Shield
CU wires Screen (or Lead or
combination of both).
6- Aluminum Laminated tape.
7- PE outer sheath + thin Semi-con
layer or graphite powder.
43
1
2
3
4
5
6
7
ELECTRIC CABLES HANDBOOK
Over Head Transmission line & Service Drop Cables
Overhead power lines are conductors suspended from electrical towers or poles to transmit power
over long distance. The conductors used are completely bare and made from aluminum. The
electrical and mechanical properties of the conductor depend on its construction. Here are some of
the cables used for power transmission.
Service drop cables used for low voltage transmission, it distributes the power to the civil buildings
over wooden poles.
1- Aluminum Conductors
- AAC
All Aluminum Conductor
- ACSR
Aluminum Conductor Steel Reinforced
- AAAC
All Aluminum Alloy Conductor
- ACAR
Aluminum Conductor Aluminum Alloy Reinforced.
2- Service Drop Cables:
1- Conductors types
Copper or Aluminum Conductors
2- Insulation
-
XLPE Insulation – Black color.
3- Cables type:
Duplex (2 conductors).
Triplex (3 conductors).
Quadruplex (4 conductors).
All Aluminum Conductor (AAC)
AAC transmission cable, also known as aluminum stranded conductor is made from multiple strands
of hard drawn 1350 aluminum alloy which is 99 % pure with a little bit of silicon, iron etc. it has very
high conductivity and resistive to corrosion but very poor strength to weight ratio. That is why it is
preferred short distances in the stations not for rural power transmission over long distance.
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ELECTRIC CABLES HANDBOOK
All Aluminum Alloy Conductor (AAAC)
In order to increase the mechanical strength of the AAC cable, a special aluminum alloy is used made
with magnesium and Selenium. It increases the strength to weight ratio while maintaining the corrosion
resistivity. However, the conductivity falls a bit
Aluminum Conductor Steel-Reinforced (ACSR) Cable
ACSR is also a stranded aluminum cable whose inner strands are made from galvanized steel
surrounded by strands of pure aluminum conductors. The steel core increases the tensile strength of
cable while the aluminum provides good conductivity and low weight. They are used in long distance
transmission line because we can alter the strength of its steel core to meet the requirement.
Aluminum Conductor Aluminum-alloy Reinforced (ACAR)
It is made of pure aluminum conductors surrounding an aluminum core. The structure of ACAR
resembles ACSR but instead of its core made from galvanized steel, it is made of aluminum alloy which
increase the overall conductivity (ampacity) while maintaining the tensile strength if ACSR.
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ELECTRIC CABLES HANDBOOK
Bundled Conductors:
Due to high voltage transmission of above 132KV over long distances, a phenomenon occurs in the
conductors known as corona discharge. High voltage ionizes the air around it which causes power loss
as well as interference in the communication lines nearby. To reduce this effect 2 or more than 2
conductors are used per phase also known as bundled conductor. These conductors are made from
same materials and are equally separated by a spacer.
Labeling of Cables
The labeling of the cables is very important and it provides a lot of information regarding its insulation
types, numbers of wires and the gauge of the wires. Take a look at some of labels written on the wires
commonly used in home wiring.
• 14-2G: The cable contains two insulated wires and a ground wire; individual wire is 14-gauge.
• 14-3G: The cable contains three insulated wires and a ground wire; individual wires are 14-gauge.
• 12-2 w/G: The cable contains two insulated wires with a ground wire; individual wires are 12-gauge.
• 12-3 w/G: The cable contains three insulated wires with a ground wire; individual wires are 12gauge.
• 600 V: This Cable is rated for a maximum of 600 volts; commonly used NM cable for home wiring.
• TYPE NM-B: NM stands for Non-metallic, it is a non-metallic sheathed cable of type-B; this is the
commonly used cable for wiring appliances and devices in home.
The most important label of them is about the insulation or the plastic coating around the conducting
wires. Here are some of the common labels written on wires.
THHN
THWN
THW
XHHN
•
•
•
•
The meaning of each letter used in the labels above is given below:
T: Thermoplastic insulation, a fire-resistant material
H: Heat-resistant; able to withstand temperatures up to 167 F (75 °C).
•
•
•
•
•
46
HH: Highly heat-resistant; able to withstand temperatures up to 194 F (90 °.
W: “Wet,” or approved for damp and wet locations; this wire is also suitable for dry locations
X: Insulation made of a synthetic polymer that is flame-retardant
N: Nylon-coated for resistance to oil and gasoline
ELECTRIC CABLES HANDBOOK
Residential Wiring Cables
The residential wiring from the utility pole to the appliances or devices inside the home is divided into
mainly five types.
Service Drop Cable:
It is the cable between the utility pole and the consumer’s premises or building. The service drop cable
is an overhead electrical line from the pole to the service weatherhead of a house. The service drop
cable can be of many types given below:
Duplex Cable: The duplex service drop cable is a two core conductor i.e. it has two conductors; an
insulated conductor for phase line and a bare conductor for neutral line. It is used for supplying a single
phase power to the building.
Triplex Cable: The Triplex service drop cable is a three core conductor. It has two insulated conductors for
phase line and a bare conductor for neutral line.
Quadruplex Cable: The Quadruplex service drop cable is a quad or four core conductors. It has 4
conductors; three of them are insulated conductors for phase lines and a bare conductor for neutral
line. It is used for supplying a 3 phase power supply from the utility pole to the building.
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ELECTRIC CABLES HANDBOOK
The phase conductor is an AAC cable while the neutral conductor is available in AAC/AAAC/ACSR.
The insulation used on these cables is XLPE that protects these conductors from moisture, heat etc.
Main Feeder Wires:
The main feeder cables & wires supply the power from the service weatherhead to the building. The
cables used for this purpose are 600v THHN, solid or stranded with the rating of 25% more than the
maximum required load.
Panel Feed Wires:
The panel feed wires supply power to the main distribution junction box. It is usually black insulted
THHN cables with rating of 25% more than maximum load current
Non-Metallic Sheathed Wires:
The non-metallic or NM sheathed wires are used for in-house wiring. It may consist of 2 or more than
2 insulated conductors with an insulated or bare ground conductor. There is another layer of plastic
XLPE sheathing for more protection. The latest version NM type-B is currently used by electricians for
interior installation. The conductors could be solid or stranded. The stranded conductors are easier to
route through conduits.
Single Conductor Wire
Single Conductor wire is the most popular choice for electrical layout inside a home. It is available in
multiple gauges, color (for phase, neutral and ground identification) and solid or stranded conductors.
A single solid wire provides better connections but single stranded wires are easier to route through
conduits. Both of them are available in THW and THHN insulation.
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ELECTRIC CABLES HANDBOOK
Communications Cable
The types of cables and wires that are used for communication or signal transmission purposes are
called communication cable. There sole purpose is to transmit information. Here are 3 types of
communications cables:
Coaxial Cable
Coax or coaxial cable is type of electrical cable made from four layers, forming coaxial shape (having
common axis or center). The central part of coaxial cable is a conductor covered by an insulating plastic
layer which is surrounded by a metallic shield. On top that is a fourth layer of plastic insulation.
The coaxial cable is used for transmission of high frequency signal. This is why the metallic shield is
used for blocking noise interference. It is commonly used for cable television signal distribution, signal
transmission between antennas, transmitter and receiver.
The coaxial cable is further divided into various types and each of them has their own application.
Hard line Coaxial or Helix Cable
Hardline coaxial or mostly known by its trademark name Helix cable is a thick coaxial cable with its
center solid conductor made from copper and the shield made from copper or silver tubing. It is
specifically used for high frequency broadcast transmission. It can carry hundreds of channels and is
usually installed between a transmitter on ground and aerial antenna.
Radiating or Leaky Coaxial Cable
Radiating or leaky coaxial cable is another type of coaxial cable where the shield is deliberately
designed in such way to radiate RF waves. The shield is made with slots tuned for specific RF
wavelength that provide bi directional leakage effect between transmitter and receiver. This type of
coaxial cable is used in places where antenna is not feasible such as underground tunnels, elevator
shafts etc.
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ELECTRIC CABLES HANDBOOK
RG-6 Coaxial Cable
RG-6 is the most common type of coaxial cable used for signal transmission in residential and
commercial applications. It is made from a solid copper wire with plastic insulation covered by an
aluminum foil and a braided shield for protection against interference. It is used for audio and video
signal transmission in application such as cable TV, Satellite TV signal and radio etc.
Triaxial or Triax Cable
Triaxial is another type of coaxial cable which includes another layer of insulation and shield over the
top of existing shield. The second or outer shield is grounded to protect the inner shield from
electromagnetic interference.
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ELECTRIC CABLES HANDBOOK
Twin-axial or Twinax Cable
Twinax cable is type of coaxial cable similar to RG-6 but with two inner conductors instead of one. The
two insulated inner conductors are twisted together surrounded by a braided shield. It is used for highspeed short-range signal communication usually for 10 Gigabit Ethernet Network.
Semi-rigid Coaxial Cable
Semi-rigid coax cable is another type of coax cable where the outer sheath is from solid copper with an
inner conductor. The outer shield provides better interference protection. Due to the tube like structure
of the shield, it is not very flexible and is not meant to bend after initial forming.
Rigid Line Coaxial Cable
The rigid line coax cable is a modified form of semi-rigid cable made from two concentric tubes (shield)
that provides extra protection for high power signal. Such cables are not meant to be bent which is why
elbow and interconnects are used for bending. They are used for high power signal transmission
between RF components of a transmitter and antenna.
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ELECTRIC CABLES HANDBOOK
Twisted Pair Cable
This type of communication cable is made from two insulated wires twisted together to form a twisted
pair. The purpose of twisting is to reduce the electromagnetic interference or noise. They are used in
Ethernet network and telephone communication.
They are further divided into two types based on their noise protection.
Unshielded Twisted Pair (UTP) Cable
The UTP cables do not have any extra shield for protection against noise. They twisted pairs may
reduce the noise but it still affects it. Various categories of UTP cables are used in residential and
commercial building with various bandwidth e.g. CAT1, CAT2 etc.
Shielded Twisted Pair (STP) Cable
The STP cable has an extra layer of foil that protects the wires from electromagnetic interferences.
They are used for high-end applications where the cables may get affected by external environmental
interferences.
Fiber Optic Cables
Fiber optic or optical fiber cable is a type of communication cable made of flexible, transparent glass
fibers known as optical fibers that transmit data in the form of light. The fiber’s thickness is
approximately equal to human hair and each individual fiber is covered with plastic insulation.
There is another external protection layer that protects the fibers from interference.
The fiber optics cable is classified into two main types;
Direct-Buried Cable (DBC)
It is a type of cable used for communication and power transmission. It is specifically designed to be
buried directly underground without the need of extra insulation, sheathing or piping. It is made of
bundles of fiber optic cables with a thick metal core for stiffness. It has multiple layers of protection such
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ELECTRIC CABLES HANDBOOK
as plastic insulation layer, waterproof layer as well as shock absorbing gel etc. to protect it from heat,
moisture and other underground factors.
Non-Metallic Sheathed Cable (NM, NM-B)
The non-metallic or NM sheathed cable or known by its trademark name “romex” cable is a type of
electrical cable whose outer sheath is made of plastic that protect the inside conductors. It is commonly
used for residential electrical wiring.
There are two types of NM sheathed cable based on number of conductors;
Two wires NM sheathed cable: This type of cables has two separately insulated conductors with a
bare conductor for ground connection that makes a total of 3 conductors. It comes in various gauges
for various ratings and it is labeled as “<gauge> – 2 WG”. It means this cable contains 2 wires plus a
grounding wire.
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ELECTRIC CABLES HANDBOOK
Three wires NM sheathed cable: this type of cable contains 3 insulated wires with a bare grounding
wire. It is used for three phase application this is why the individual conductor is marked with different
phase color for identification.
The NM wires are available in solid as well as stranded form. The solid conductor provides better
connection at terminals but it is difficult to route through pipe or conduits. While the stranded conductors
are more flexible and easier to route through conduits.
The NM-B (B for building) is a type of NM cable especially used for indoor building wiring. They are
used for wiring inside wall and floors but not to be used in wet places such as external wiring.
Metallic Sheathed Cable (Armored Cable, AC or BX, MC)
Metallic sheathed cable, as the name suggest is a type of armored electrical cable with a metallic
protection over the insulated conductors. The conductors are separately insulated with plastic layer
which is surrounded by a metallic sheath for extra protection. The metal sheath can be braided or
twisted that surrounds individual or all conductors or it could a solid pipe like structure.
The metallic sheathed cables are mostly known by AC (armored cable) or BX cable and MC (metal
clad) cable. BX is the registered trade name for AC cables.
Armored Cable (AC)
Such type of metallic sheathed cables has a protective twisted or braided metallic layer usually made
of steel over its conductor. The external sheath is made of plastic. The metallic layer provides extra
mechanical strength against any sort of damage and can also be used for grounding connections. Thus
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ELECTRIC CABLES HANDBOOK
they are not used in damp or wet location as well as underground. The armoured layer can be wire
braid, steel wire or steel tape. The steel wire armored (SWA) cable is most common type of armored
cable used for power transmission.
Metal Clad (MC) Cable
The difference between AC and MC cables is that MC Cable’s metallic sheath cannot be used as
grounding wire. It has an extra green colored insulated wire for ground connection. Thus they can be
used as direct burial type and in wet locations but if they have their protective PVC outer sheath.
The metallic sheathed cables are expensive and hard to route and needs special tools for cutting or
ripping as compared to NM cable which is the best choice for residential wiring. They are used in power
supply for large appliance and external use.
Multi-Conductor or Multicore Cable:
Multi-core or multi-conductor cable has multiple conductors with insulated sheaths that are rolled into
one jacketed cable. Its job is to avoid the messy connection by having one single cable instead of 10
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ELECTRIC CABLES HANDBOOK
or 20 separate wires and save time by connecting them one by one.
The individual conductors have insulation sheath with a common housing made from insulating
material. But in some cases, there is an aluminum layer for protection against EMI (electromagnetic
interference) or an extra armored layer for more protection. The multiple core cables usually ends in a
multi-pin connector.
The cores are the number of useful connections; a simple 3-phase cable cannot be called a multi-core
cable but a cable having 2 or more then 2 separate 3-phase conductors is a multicore cable. For
example, an audio mixer has multiple input cables from microphones, the cables are joined together to
form a multi-core cable which is easier to plug in instead of plugging each cable in its own spot.
They are mostly used in electronics for data transmission in application such as:
• Transmitting audio signal to audio mixer.
•
Sending audio and video signal in gaming consoles.
•
Sending camera signal to CCU (camera control unit) in TV studios
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ELECTRIC CABLES HANDBOOK
•
Sending audio and video signal using a single cable from camera.
•
In networking.
Paired Cable
Paired cables are type of electrical cable made from a pair of two insulated conductors covered by an
insulation sheath. They are mostly used for DC application and also in low frequency AC applications.
Portable or Extension Cord
It is a flexible electrical cable with connectors on both ends to provide a temporary AC power supply. it
is usually used as extension of power source for powering portable equipment, machines and devices.
They type of insulation material used for the conductor determines its application or environment of use
(such as temperature, moisture, weather, oil etc.). While the rating of cord is determined by the size of
the wire conductor.
Ribbon Cable
This type of cable is made from multiple small grade insulated wires parallel to each other in a flat
shape that resemble a piece of ribbon thus the name ribbon cable. They are flexible and they can
handle very low voltages.
They are mostly used in electronic devices and computers to connect different internal peripheral that
require data buses like hard drives, CD drives, printers etc. Due to their flat shape, they block the airflow
inside computer which affects the cooling system. Nowadays, they are mostly replaced by round cables.
Shielded or Screened Cable
Shielded cable or screened cable is a type of electrical cable whose conductors are protected by an
extra metallic layer known as shield. The shield may be made from braided aluminum, copper or any
other metal or it could be a foil, a spiral tape or a solid layer made from the said conducting metals.
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ELECTRIC CABLES HANDBOOK
It provides protection against electrical noise or EMI (electromagnetic interference) generated by any
near electrical sources. It is eliminated by grounding the shield at one end. In power cables, the shield
layer is grounded to protect the insulation from breaking due to corona discharge as well as avoid
electrical shock.
Single Conductor Wire
Single conductor wire or most commonly known as just wire, is made of a single insulated conductor.
It is the most popular choice for residential wiring. It is available in multiple colors for phase and earth
identification. The single conductor wire has two types.
Single Stranded Wire:
Single stranded wire is made of multiple thin strands of wires that form together one conductor. The
stranded design offers flexibility thus they are suitable for applications where wires need to be bent or
twisted. Electrician prefer stranded over solid because it is easier to route through pipes in walls due to
its flexibility.
Single Solid Wire:
Single solid wire is made of single solid core with plastic insulation. The solid design offer better
connection but it is difficult to bend or twist due to its stiffness. Multiple bending might damage and
break the conductor inside. They are used in applications where there is no movement or bending
required for wires.
Submersible Cable
As the name suggest, this type of electrical cable is designed to be used in wet locations or submersed
in a liquid. The insulation used for such cables is very rugged, abrasion-resilient and extremely durable
and reliable to meet the challenges present in the installation environment. They are designed to be
used as direct buried cable.
They are available in single as well as multiple conductor design having flat or round structure to meet
its applications. The conductors are color coded to identify phase and earth connections as well as the
control wires that runs along the power conductors.
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ELECTRIC CABLES HANDBOOK
They are used in location that is physically restrictive and inaccessible. The most common use of
submersible cable is to supply power to submersible motors and pumps underwater, in agriculture
industries, underground mining or drilling purposes.
Twin-lead
Twin lead cable is a two conductor flat cable used as a balanced line to carry radio frequency RF signal.
The conductors are held apart and uniformly space by a plastic layer between them. The equal spacing
is very important because it keeps the signal from distortion. The conductors are mostly stranded to
avoid skin effects and they are insulated using the same plastic material.
They are more susceptible to external noise interference and weather conditions that is why these
factors are kept in mind during installation. Of course, the coaxial cable has better noise protection but
twin lead cable is preferred due to its low power losses.
Ladder Line
Sometimes, due to wet condition such as rain, wind etc. the water drop gets accumulated on top of the
plastic between the conductors. This causes interference in the signal. In order to avoid such condition,
a window like slots is cut into the plastic layer. The resulting wire resembles a ladder like structure, thus
the name ladder Line.
The twin lead is available in 600, 450, 300, and 75 ohm characteristics impedance. The most common
type is known by 300 ohm twin lead cable used for television sets. They are mainly used to connect the
transmitter or receiver with RF antennas in TV and Radios etc.
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ELECTRIC CABLES HANDBOOK
Underground Feeder (UF) Cable:
It is a type of non-metallic sheathed cable designed for use in wet location such as supplying power to
lamp post or street light. NM cables have a loose wrap of plastic sheath around it whereas the
conductors in UF cables are individually surrounded by a solid layer of thermoplastic that provide
flexibility and extra protection. The water-resistant insulation material allow them to be used in damp
locations such as supplying power to garden shed, lamp post. They are mostly available in gray color
outer sheath. They are the best choice for avoiding poles and exposed wire by simply running them
underground.
Flexible Cables
Flexible cables are a type of electrical cables that can withstand continues bending in moving
applications. The flexibility is achieved by using stranded conductors. They are used in automation
industries where the machines are continuously moving such as pick and place machines and CNC
based machines such engraving, milling machines etc.
The flexible cables are of two types:
Stranding in Layer
This type of cable is made from multiple layers of strands of conductor. The cores of this cables is
designed to be firm and the surrounding layers are made long. Because the outer layer stretches during
bending while the center core compresses. This type of cable is easier to manufacture and is cheaper.
The material used for such cable is flexible but too much bending might deform the cable.
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ELECTRIC CABLES HANDBOOK
Stranding in Bundles
This type of cable is achieved by braiding the conductor around each other so that the conductor
stretches uniformly when the cable bends. This type of cable is more durable because of its tension
proof core but a little stiffer than the stranded cable.
Control cables
Control cables occupy an intermediate position between power cables and communications cables.
Used for transmission of information or operating conditions of objects being controlled; and are used
where direct access to such objects is difficult or impossible.
They are widely used to connect electric instruments and apparatus, for secondary switching of
Remote-control starters and regulators, for protective relaying, control circuit and in automation.
In contrast to communications cables, control cables are capable of carrying current loads.
5
4 3
2
1
Insulation
Outer Sheath
Conductor
1. Stranded or Solid Copper
Conductor
2. XLPE Insulation with
Number marking
3. Binder tape
4. Extruded Inner
Sheath (If applicable)
5. PVC or LSHF Sheath
Cables construction based on cores principle
Control
Cables
Control
Room
Controlling
Gates
Controlling
instruments
Instrumentation cable:
Many industrial applications require cables to transmit signals from field instruments to control rooms.
Instrumentation cables carry the data from the field instruments such as (tank temp., tank pressure,
liquid level inside tank, liquid flow and other parameters) and send it to the control room.
The accuracy factor is very important for instrumentation cables, the received data in control room
shall be accurate to avoid any industrial disaster. Because of that, instrumentation cables shall be
screened individually or overall.
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ELECTRIC CABLES HANDBOOK
Tank Temp.
Tank Pressure
Control
Room
5
Oil Level
Instrumentation
Cables
4
3
2
Oil Flow
1
1. Conductor: Stranded Plain/Tinned Copper conductor.
2. Insulation: PVC FR 90°C, XLPE FR 90°C.
3. Pairing/Triads: Uniformly twisted insulated conductors with a suitable twist of lay.
4. Assembly and wrapping tape.
5. Jacket: Heat Resistant PVC Flame Retardant, Sunlight and Oil Resistant (Black).
4
3
2
1
Conductor: Stranded Plain/Tinned Copper
conductor.
2. Insulation: PVC FR 90°C, XLPE FR 90°C.
3. Pairing: Uniformly twisted insulated conductors
with a suitable twist of lay, wrapped with
polyester tape.
4. Jacket: Heat Resistant PVC Flame Retardant,
Sunlight and Oil Resistant
1.
Thermocouple cables:
This type of cables is mainly used for temperature measurements. It allows temperatures to be
measured electronically.
There are many types of thermocouple cables classified according to temp level and conductor’s type.
For example: type N, type J, type K, … each type has special conductor alloy material.
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ELECTRIC CABLES HANDBOOK
Fieldbus cables:
This type of cable mainly used as backbone of industrial network. Its capacity and speed is greater
than ordinary instrumentation cables.
Special standard and test for fieldbus cable. (it is always orange color).
Instrumentation cables are connected to fieldbus cable in order to travel for long distance by one cable.
Tank Temp. (Thermocouple cable)
Tank
Pressure
Control
Room
Oil Level
Oil Flow
Foundation Fieldbus Cable
Intrinsically Safe (IS) cables:
This type of cable mainly used in hazard areas which include
toxic and harmful gases. The cable recommended to be filled
and well-sealed in glands, joints and terminations. Spaces and
gaps inside the cable may allow gases moving from area to
another. It is always blue color.
MULTI PAIR/TRIAD WITH INDIVIDUAL & OVERALL SHIELD, INSTRUMENTATION CABLE 90°C / 500V
1. Conductor: Plain/Tinned
1.Stranded
Conductor:
Plain/Tinned
Copper
conductor.
Stranded Copper conductor.
2.2.Insulation:
PVC
90°C,
XLPE
Insulation: PVC 90 C, XLPE
3.3.Pairing/Triads:
Twisted
Pairing/Triads: Twisted
insulated conductors
a a
insulated
conductorswith
with
suitable lay.
suitable lay.
4. Individual Screening/Shield: Aluminium-
6. Overall
Screening:
6. Overall
Screening:
4. Individual
Screening/Shield:
Aluminium-tape
Polyester
(AL-PET foil) laminated
Aluminium-Polyester
Aluminium-Polyester
Polyester (AL-PET foil) laminated tape
with 100% coverage.
laminated
tape with
with
laminated
tape with
5. Assembly
and wrapping: The pairs/triads100% 100% coverage.
100%
coverage.
coverage.
5. Assembly
and wrapping:
The pairs/triads
assembled
together and
wrapped with a
7. Jacket:
PVC Flame
7. Jacket:
PVC Flame
assembled together and wrapped with a
polyester tape.
Retardant
Retardant
polyester tape.
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ELECTRIC CABLES HANDBOOK
Control Cables vs. Inst. Cables
ITEM
Control Cable
Instrumentation Cable
Type
Power (carrying current)
Between power and telecommunication (carrying
industrial signals)
Principle
Cores
Pairs, Triads
Screening
It may be required
Cables shall be screened (individual or overall).
Application
For controlling purposes,
(petrochemical, civil & Factories)
For industrial signaling purposes, (petrochemical
& Factories).
OIL & GAS, and PETROCHEMICAL CABLES
CABLE PERFORMANCE FOR COLD & HOT ENVIRONMENTS
VAPOR / GAS TIGHT REQUIREMENTS
MINERAL OIL RESISTANT
RESISTANT FOR MUD & DRILLING FLUID WATER BASED (Calcium-Bromide)
FIRE RESISTANT, REDUCED EMISSION OF FUMES & HALOGEN ACID GASES
HYDROCARBONS RESISTANT
MECHANICAL RESISTANT
WATER RESISTANCE
BULLET PROOF
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ELECTRIC CABLES HANDBOOK
PETROCHEMICAL
ARMORED CABLE
PIPELINE SHIELDED
CABLES
ONSHORE
CABLE
DRILLING
CABLE
RAILWAY SIGNALLING CABLES
1
2
3
4
5
6
1
2
3
4
5
6
7
7
8
1- Bare copper conductor 0.9 mm,
1.4 mm or 1.8 mm diameter.
2- PE insulation.
3- Singles stranded in layers to
form the core.
4- Core wrapping.
5- PVC FR sheath.
6- Steel tape armouring, 0.3 mm.
7- PVC FR protective cover
1- Bare copper conductor 0.9 mm,
1.4 mm or 1.8 mm diameter.
2- PE insulation.
3- Singles stranded in layers to
form the core, with wrapping.
4- PVC FR sheath.
5- Copper shield.
6- PVC FR sheath.
7- Steel tape armouring, 0.3 mm.
8- PVC FR protective cover
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ELECTRIC CABLES HANDBOOK
SUBMARINE CABLES
1. Conductor: copper,
circular stranded compacted,
longitudinally watertight
2. Conductor screening:
extruded semi-conductive
compound
3. Insulation: XLPE
4. Insulation screening:
extruded semi-conductive
compound
5. Screen: copper wires and
copper helix, swelling
powder or tape
6. Laminated sheath:
Aluminium tape bonded to
overlaying PE sheath plus
conductive coating.
7. Fiber optic cable, optional
8. Fillers: polypropylene strings
9. Binder tapes
10. Bedding: polypropylene
strings or polyester tape
11. Armour: galvanized round
steel wires
12. Serving: bituminous
compound, hessian tapes,
polypropylene strings with
Coloured stripe.
PHOTOVOLTAIC (SOLAR) CABLES
Conductor material: Copper / Tinned Copper
Insulation material: Thermoplastic, Halogen-free,
XLPE-FR, HEPR, EPR.
Sheath: Crosslinked Polyolefin.
Cable exposed to sunlight must be Sunlight
Resistant, Low smoke, Non-halogenated, Flame
retardant.
OPGW CABLE
An optical ground wire (OPGW) is an optical
fiber composite overhead ground wire, used in
overhead power lines. Optical fibers are placed in a
plastic tube, and tube is inserted into a stainless steel,
aluminum, or aluminum-coated steel tube. The buffer tubes
are filled with grease to protect the fiber unit from water and
to protect the steel tube from corrosion, the interstices of the
cable are filled with grease. The tube is stranded into the
cable with aluminum, aluminum alloy or steel strands.
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ELECTRIC CABLES HANDBOOK
Low Smoke Halogen Free (LSHF) cable:
In case of fire, when the cable burned, smoke and halogens will be raised up. The smoke will not allow
the people to see the exits and the halogens will harm them. Therefore, it is strongly recommended to
apply LSHF cables (LSHF material for inner and outer jacket) inside building, transportation application,
and crowded area.
Low Smoke (LS) cable:
3
IEC 61034 (Low Smoke Emission) : Smoke opacity measurement in a 27 m room, during the
burning of a cable sample (25mn), and 40mn after burning is completed. In other words, 60 % of the
transmitted light shall be detected by the sensor in the other side of the light source.
Halogen Free (HF) cable:
The halogens are five non-metallic elements found in Group 7 of the periodic table. The Halogens are: Fluorine. – Chlorine. – Bromine. – Iodine. – Astatine. (PVC can be low smoke but will never be halogen
free material).
Halogenated materials will release corrosive and toxic gases if ignited in a fire. The corrosive element of
these gases has the potential to damage electronics wherever the smoke travels, and the toxic element
can be potentially hazardous to persons if they cannot easily evacuate from the area.
IEC-60754-2 recommended values to be classified as “halogen free”: The pH value should not be less
than 4.3 when related to one liter of water.
Flame Retardant cable:
In case of fire, when the cable burned, the fire and the flame will spread very fast over cables.
Therefore, it is strongly recommended to apply flame retardant cables (flame retardant material for inner
and outer jacket) inside building and crowded areas.
Most famous international standard for flame retardant is IEC 60332 (cat A, B or cat C).
Cat A is more aggressive test.
Temperature: 800°C
Cat A: 7 l/m of burning material
Cat B: 3.5 l/m of burning material
Cat C: 1.5 l/m of burning material
Test duration
Cat A: 40 min.
Cat B: 40 min.
Cat C: 20 min.
Fire Resistant cable:
Used for cables required to be in duty for some time during fires in order to protect people or to prevent
big disaster. In case of fire, cable burns, fire will destroy cable’s materials (including the insulation)
reaching to the conductors. In this case, cables will not function well, and will fail.
For this reason, we apply MICA tape over the conductors to allow us to take urgent action like: fire
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ELECTRIC CABLES HANDBOOK
alarm, firefighting, open gates, open valve to move dangerous liquid or gas from tank, etc...
Most famous international standard for fire resistance are IEC 60331 & BS 6387 (C, W, Z).
Mica
Tape
Fire Resistant
Control Cables
Control
Room
Fire
Cathodic protection (CP)
It is a technique used to control the corrosion of a metal surface by making it the cathode of an
electrochemical cell. A simple method of protection connects the metal to be protected to a more
easily corroded “sacrificial metal” to act as the anode.
The sacrificial metal then corrodes instead of the protected metal. For structures such as long pipelines,
where passive galvanic cathodic protection is not adequate, an external DC electrical power source is
used to provide sufficient current.
Cathodic protection systems protect a wide range of metallic structures in various environments.
Common applications are: steel water or fuel pipelines and steel storage tanks.
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ELECTRIC CABLES HANDBOOK
COPPER CLAD ALUMINUM CONDUCTOR
A copper-clad aluminum composite wire has a core that is made of Al-Mg alloy and circumferentially
cladded with copper or a copper alloy.
•
•
•
•
•
Copper by volume, 10% or 15%.
Conductivity 63% - 67% IACS.
High operating period, and resistant to mechanical stresses.
Flexible, lightweight, and excellent for use as building wires.
If the size is equal, we can get a length equivalent to 7 times the length of the copper cable, and
one third of the weight.
SUPER CONDUCTOR CABLES
IDEA:
In superconducting materials, the superconductivity state exists as long as the temperature, current, and
magnetic field are all below their critical values.
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ELECTRIC CABLES HANDBOOK
CONSTRUCTION:
1- Copper former Tube
2- Hollow former
3- HTS phase layers
4- Dielectric Polypropylene Laminated Tapes
(PPLT)
5- HTS layers (High Temperature Superconductor)
6- Copper Screen
7- Liquid Nitrogen
8- Inner Cryostat Tube wall (Cooling Regulator)
9- Super Insulation
10- Outer Cryostat Tube wall (Cooling Regulator)
11- PE Sheath
The Superconducting Material is the Bismuth Strontium
Calcium Copper Oxide (BSCCO), from which high
temperature superconductor (HTS) Strips or Wires are
manufactured, which can withstand a temperature of 110°C.
BSCCO: Bi2 Sr2 Ca2 Cu3 O10 (Bi-2223)
•
•
•
Multi-Filamentary structure in silver matrix.
Conductor current densities of 100 A/mm2 and above.
Available in km length.
HTS strips are wrapped around a normal conductor and are surrounded by a high voltage insulator
that acts as an insulator. Furthermore, the heart of the entire cable is isolated against ambient
temperature by a tube called cryostat - HTS straps are usually cooled by liquid nitrogen that is pumped
through cable cryostat. As a result, the insulator itself is immersed in liquid nitrogen – this cable is
generally called a cold insulator cable.
ADVANTAGES:
1 - Improve System Reliability
2 - Meeting increased energy demands without a need for new power stations.
3- Increase power transmissions significantly than normal conventional cables.
4- The loss in the cable is very low due to the fact that the resistance is almost zero.
5- Low Impedance
6 - Its size is lower than normal cable and does not require new underground channels or tunnels.
7- It does not affect the surrounding environment.
For example, compared to conventional cables:
Three normal 66 kV power transmission lines - with these lines, if the demand for electric power expands
threefold, six new lines must be installed to meet this demand.
With a single 3-Phase Super-Conductor cable, we will have a 200% increase in power capacity without
installing a new six normal cables.
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ELECTRIC CABLES HANDBOOK
SPECIALTY CABLES
1.
2.
3.
4.
5.
6.
7.
8.
9.
Low Smoke Halogen Free Cables.
Cable with Mica Taping in Case of Fire.
Control Cables.
Instrumentation Cables.
Oil & Gas, and Petrochemicals Cables.
Railway Signaling Cables.
Submarine Cables.
Photovoltaic (Solar) Cables.
Ethernet Cables.
LOW SMOKE HALGEN FREE CABLES
Why is LSHF, LSZH Cable?
(Low Smoke Halogen Free, Low Smoke Zero Halogen)
A plastic containing halogen can release Hydrogen Chloride, Hydrogen Fluoride, and other dangerous
gases when burned.
Safety LSZH cables are used in public spaces—train and subway, cars, airports, hospitals, boats,
commercial buildings - where toxic fumes would present a danger in the event of a fire.
Reducing smoke in general, and toxic smoke in particular, will save lives.
Construction
1. Conductor: Annealed Copper
2. Insulation: LSHF Po, HFFR XLPE
3. LSHF Filler
4. LSHF Binding Tape
5. LSHF Inner Sheath
6. Steel Wire Armor SWA
7. LSHF Outer Sheath
1
2
3
4
5
6
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LSHF POWER CABLES
HFFR (Halogen Free Flame Retardant)
Insulation & Sheathing Materials
CABLES WITH MICA TAPE IN CASE OF FIRE
Those cables are designed to keep working for long time in special considerations related to safety of
people in the scene of fire.
Conductor:
Wrap a MICA tape on the conductor as it sustains high temperatures and works as a buffer if fire
damages the original Insulation.
Insulation:
Fire resistant XLPE HFFR insulation instead of traditional materials – and in cables operate at high
temperatures, we use dielectric Fluoro-Polymer Based or Isolating Mineral Filled component.
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ELECTRIC CABLES HANDBOOK
Outer Sheath:
Material of LSHF POLYOLYFIN which in case of fire would be low smoke and Toxic-Free & HalogenFree.
Sheath: LSHF Compound
Copper conductor
Insulation: XLPE - FR,
Fire Barrier: Mica Tape
LSHF Compound
Those Cables are often used in Lighting Circuits, Fire Alarm Circuits, Thermocouples, and for
Ovens & Boilers.
Silicon Rubber Insulated Wires and Cables
Features
• Silicon rubber has an excellent environmental property because it does not generate a halogen gas
during combustion.
• It has the heat resistance of 180°C.
• It can be used under low temperature because the brittleness temperature is -60°C.
• The flame retardant property meets the requirement of JIS C 3005 4.26.2 b) (Inclined test).
• It has the excellent properties of flexibility.
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ELECTRIC CABLES HANDBOOK
TUBE ENCAPSULATED CABLES (TEC Cable)
TEC Cables (Tubing Encapsulated Conductors) are cables that have the traditional characteristics of
standard wires or cables, as they have some form or copper conductor surrounded by an insulation material
or jacket. The difference comes when a tubing layer surrounds the product with an armored metal
component. Lastly, a final layer encapsulates the entire cable.
TEC cables can withstand temperature ranges from 150°C to 300°C.
Application: Monitor the temperature, pressure and other parameters in every wells.
Tube Materials: 316L, Alloy 400, Alloy 825, Alloy 625.
OD of Tube: 1/8'', 1/4'', 1/2'', 3/8'', 3/4'', 5/8''.
Wall Thickness: 0.028'', 0.035'', 0.049'', 0.065'', 0.083''.
TPR Encapsulation: Bare, Round, Square, Color-coated, Flat-packed.
CABLES for WIND POWER GENERATION
Main kinds of cables used within the Nacelle system include low voltage (LV) and mediumvoltage cables. In the nacelle, cables carry low-voltage control signals, data, and communication
signals. Other cables carry power down from the generator and are used to switch gear at the tower
base.
Power cables are mainly of copper conductor,
Rubber Insulated and Sheathed.
Mineral Insulated Cables (MI & MICC)
Mineral Insulated cable MI or Mineral-Insulated Copper-Clad Cable MICC consists of copper or
thermocouple wires inside a copper, stainless steel, or Inconel® sheath, insulated by packed minerals
such as magnesium oxide (MgO). Magnesium oxide makes an excellent electrical insulation material
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ELECTRIC CABLES HANDBOOK
because it resists oxidation and ionizing radiation, and it is both chemically and physically stable at high
temperatures.
Construction:
MI cable is made by placing copper conductor inside a circular copper tube and filling the intervening
spaces with dry magnesium oxide powder.
The overall assembly is then pressed between rollers to reduce its diameter (and increase its length). Up
to seven conductors are often found in an MI cable, with up to 19 available from some manufacturers.
Since MI cables use no organic material as insulation (except at the ends), they are more resistant to
fires than plastic-insulated cables.
MI cables are used in critical fire protection applications such as alarm circuits, fire pumps, and smoke
control systems. In process industries handling flammable fluids MI cable is used where small fires would
otherwise cause damage to control or power cables. MI cable is also highly resistant to
ionizing radiation and so finds applications in instrumentation for nuclear reactors and nuclear physics
apparatus.
MI cables may be covered with a plastic sheath, Coloured for identification purposes.
The plastic sheath also provides additional corrosion protection for the copper sheath.
The metal tube shields the conductors from electromagnetic interference. The metal sheath also
physically protects the conductors, most importantly from accidental contact with other energized
conductors.
Main Purpose & Use:
•
•
•
•
•
•
•
•
•
•
•
•
Nuclear reactors
Exposure to dangerous gasses.
Air pressurization systems for stairwells to enable
building egress during a fire.
Hospital operating rooms.
Fire alarm systems.
Emergency power systems.
Emergency lighting systems.
Temperature measurement
devices; RTDs and Thermocouples.
Critical process valves in the petrochemical
industry.
Public buildings such as theatres, cinemas,
hotels.
Transport hubs (railway stations, airports etc.).
Hot areas e.g. power stations, foundries.
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ELECTRIC CABLES HANDBOOK
Cable Choice
The choice of the appropriate cable depends on several considerations, including conditions for site
location,
surroundingenvironmentandotherconsiderationsrelatedtothefunctioningandoperationofthecableitself.
We should consider the following when we choose a cable:
* Conductor type
* Type of insulation
* Armored or Unarmored
* External protection adequacy to the environmental and operating conditions.
In all cases, cables construction and testing are regulated through different International Standards.
IEC 60502-1
IEC 60227 IEC 60245
BS 4553
BS 5467
BS 6004
BS 7540
IEC 60502-2
BS 6622
BS 6724
BS 7835
AEIC CS7
AEIC CS9
ICEA S-97-682-207
IEC 60840
BS 7912
ICEA_S_108_720_2004
IEC 62067
ICEA_S_108_720_200
IEC 61089
IEC 60889
BS 215
ASTM B231M
ASTM B232
DIN 48201 DIN 48204
ICEA-S-93-639
BS 6485
BS 7884
Rated Voltage for each Category in International Standards:
LV Cables & Wires: 300/500 V
MV Cables: 3.6/6 (7.2) kV
450/750 V
6/10 (12) kV
0.6/1 (1.2) kV
8,7/15 (17,5) kV
1.8/3 (3.6) kV
12/20 (24) kV 18/30 (36) kV 18/30
19/33 (36) kV
HV Cables: 26/45-47 (52) kV
36/60-69 (72.5) kV
64/110-115 (123) kV
76/132-138 (145) kV
87/150-161 (170) kV
EHV Cables: 127/220-230 (245) kV
220/380-400 (420) kV
160/275-287 (300) kV
190/330-345 (362) kV
290/500 (550) kV
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ELECTRIC CABLES HANDBOOK
SUMARRY OF IEC STANDARDS
IEC 60228
CONDUCTORS FOR INSULATED CABLES
This International Standard specifies the nominal cross-sectional areas, in the range 0,5 mm2 to 2
500 mm2, for conductors in electric power cables and cords of a wide range of types.
Requirements for numbers and sizes of wires and resistance values are also included.
These conductors include solid and stranded copper, Aluminum and Aluminum alloy conductors in
cables for fixed installations and flexible copper conductors.
IEC 60502-1
IEC 60502-1
CONTENTS:
1- Cable KV Ratings
2- Materials for Insulation & their Nominal specified thicknesses.
3- Materials for Bedding & their Nominal specified thicknesses.
4- Materials for Sheathing & their Nominal specified thicknesses.
5- Assembly of Cores.
6- Armoring (DST or SWA, AWA or DATA).
7- Screening (if required).
8- Testing of Cables:
8.1. Routine T
8.2. Sample Test
8.3. Type Test
9- Fictitious Calculations of Cable Dimensions.
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ELECTRIC CABLES HANDBOOK
IEC 60502-2
CONTENTS:
1- Cable KV Ratings
2- Materials for Insulation & their Nominal specified thicknesses.
3- Materials for Bedding & their Nominal specified thicknesses.
4- Materials for Sheathing & their Nominal specified thicknesses.
5- Assembly of Cores.
6- Armoring (DST or SWA, AWA or DATA).
7- Screening.
8- Testing of Cables:
8.1. Routine Test
8.2. Sample Test
8.3. Type Test
9- Fictitious Calculations of Cable Dimensions.
10- Installation & AMPACITY tables
IEC 60840
Power cables with extruded insulation and their accessories for rated voltages above
30 kV (Um = 36 kV) up to 150 kV (Um = 170 kV) – Test methods and requirements
CONTENTS:
1- Scope
2- Normative references
3- Definitions
4- Voltage designations and materials
5- Precautions against water penetration in cables.
6- Cable characteristics.
7- Accessory characteristics.
8- Test conditions.
9- Routine tests on cables
10- Routine tests on accessories
11- Sample tests on cables.
12- Type tests on cable systems
13- Type tests on cables
14- Type tests on accessories
15- Electrical tests after installation.
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ELECTRIC CABLES HANDBOOK
IEC 62067
CONTENTS:
1- Scope
2- Normative references
3- Definitions
4- Voltage designations and materials
5- Precautions against water penetration in cables.
6- Cable characteristics.
7- Accessory characteristics.
8- Test conditions.
9- Routine tests on cables and on the main insulation of prefabricated accessories
10- Sample tests on cables
11- Sample tests on accessories.
12- Type tests on cable systems
13- Prequalification tests of the cable system
14- Electrical tests after installation.
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