This document provides information on instrumentation cables, including their purpose, applicable standards, typical configurations, conductor types, insulation, screening, armoring, sheathing, and protection. Instrumentation cables are multiple conductor cables that convey low energy electrical signals for industrial processes. They are commonly used in industrial projects to connect electrical instrument circuits and provide communication services around process plants. The document discusses cable components, materials, and specifications according to various standards like BS 5308.

1. Instrumentation - Cables
GSS Srinivas

2. Introduction
to Cables
General
Specification
BS 5308
Conductor Insulation
and Jacket
Shield Armoring Selection
of cable

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Introduction to Instrumentation Cables
Used within industrial manufacturing plants for control, communication, data and voice
transmission signals. These cables are used typically in industrial projects. They are used to
connect electrical instrument circuits and provide communication services in and around process
plants with detail signal transfer.
Purpose
Instrumentation cables are multiple conductor cables that convey low energy electrical signals used for
electrical power systems and their associated processes.
Applicable Standards
BS 5308 or EN 50288-7 Basic Design; IEC 60332-1 Flame Retardant; IEC 60332-3 Fire retardant (cat. C or A according to requirements);
IEC 60754-1 Halogen free properties (only for LSZH cables) IEC 61034-2 Low smoke emission (only for LSZH cables)

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Instrumentation Cables -Typical Configuration
BS 5308
Part list:
1. Conductor
2. Insulation to conductor
3. Individual Screening
4. Overall Screening
5. Bedding
6. Armoring
7. Sheath
8. Drain wire
9. Non hygroscopic
Type 1
Polyethylene insulated
Un Armored
PVC Sheathed
Individually and
collectively Screened
Part 1
Type 2
Polyethylene insulated
Armored- Steel wire
Individually and
collectively Screened
Type 1
PVC insulated
Un Armored
PVC Sheathed
Individually and
Collectively Screened
Type 2
PVC insulated
Armored – Steel wire
PVC Sheathed
Individually and
collectively Screened
Part 2
Screening:
Collectively screened by a
laminated, bonded
aluminum/ polyester tape.
Drain Wires
The metallic side of the
screen are in contact with
one or more tinned
annealed copper drain wire
Pair
Two insulated conductors
uniformly twisted together
to form a pair with max. lay
length of 100mm
7 6
5
4 3
2
1
8
6

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Conductors
For instrumentation cables conductors are generally
plain annealed electrolytic copper wire for signal
transmission or special alloy, for thermocouple
/compensating cables. Conductors can generally be
according to EN 60288: class 1 (U) Solid, class 2
(R ) stranded and class 5 (F) flexible
Type of conductors are chosen according to electrical
characteristics, required flexibility, type of connection
systems or specific installation conditions, for
example:
 Class1 solid conductor is preferable for
permanent installation, crimping termination,
 In presence of vibration or movement or reduced
bending radius is preferable class 5 flexible
conductor,
 In presence of corrosive atmosphere, high
temperature or to facilitate the soldering is
preferable tinned conductor.
Conductor
Size
BS EN 60228
Stranding
Bare or Tinned

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Conductors – Class 1, Class 2 and Class 5&6
Plain Or Metal coated annealed
Wire Coatings:
Applied on the conductors to prevent some insulations from attacking or adhering to copper. Also
helps in soldering and prevents deterioration of copper at high temperatures
Annealing:
A process in which the conductor is heated to over 700 deg F and allowed to cool. This will allow
conductors to bent without breaking, remove stiffness and improve flexibility.
Wire Bars:
Approx. 200 pound billet of cu, roughly
54” long X 3-7/8” wide X 3-5/8” high
used as the feedstock for making the
rod
Rods
A 5/16” or 3/8” dia. rod
drawn from wire bars to
make solid conductors &
individual strands
Stranding
Twisting together small
wires to form a single
conductor. Provide
flexibility, ease of handling
and vibration resistance
Bunch Strand
(ASTM B-174)
A conductor formed by
simple twisting in one
direction of many small
wires. Used in flexible
cords, flexible control cables
and flexible lead wires
Concentric Strand
( ASTM B 8)
A conductor is formed as a
layer with 7,19,37,61 or 91
wires. Normally adjacent
layers are reversed
direction. Control cables
favor 7 and 19 wires.
Rope Lay – Bunch
Stranded members and
Concentric stranded
members
(ASTM B-172&3)
7 or 19 strands form a
conductor. Used in portable
power cables and welding
cables

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Insulation and Jacket
Insulation applied over conductors for electrical isolation between conductors or from ground
Jacket applied over conductor insulation or cable core for mechanical, chemical or electrical protection
01
02
03
04
05
06
07
08
Size
Electrical
Physical
Chemical Resistance
Environmental Conditions
Service life
Reliability
Flexibility
Wall Thickness
Capacitance,
Attenuation, velocity
of propagation,
Dielectric Strength,
working voltage and
Dielectric constant
Elongation, Tensile Strength,
Temperature rating ,
Flexibility, Flammability,
Resistance, Specific gravity
Chemicals can destroy
cable materials.
Extreme temperatures
brittle at low and soft at
high. Vaccum leaches oils
out of cables. Radiation
cause damage to cables
Ideal cable system should
be engineered to last the
life of the product in any
environmentligula
Ability of a cable to bend
09 Radiation resistance
10
Smoke Generation and Flame
Resistance
Ability of a cable to burn,
construction dependent
and industry standard
apply
Is based on the
both durability and
signal integrity
Radiation index is
the absorbed dose in
Gray (Gy) of the
material after
exposure having 50%
elongation of brake
of its unaged value
at least.

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Insulation
Working conditions need to be taken into
consideration to choose the right insulation
material.
Material can be divided into thermoplastic
and thermoset (cross linked).
Thermoplastic material are more sensitive to
high temperatures, as material melts at the
increase of temperature, while thermoset,
due to stable polymeric chain bonds are
more resistant to temperature and
deformation.
Most popular insulations are PE and PVC for
general installation conditions and LSZH
thermoplastic materials (low smoke zero
halogen).
Other class includes, XLPE, silicone rubber,
other rubbers such as EPR, HEPR, EVA.
Special techno polymer can be used in case
of specific installation condition, such as
fluoro- polymer or techno-polymer materials.
For fire resistant cables two types of
insulation are used: silicone or mica tape
plus XLPE (or other thermoset compounds).
Insulation
Type
BS 6234/50363/7655
Wall Thickness
Temperature
Voltage

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Screening
Electrostatic noise can be
reduced by screening around the
cable, around each pair or both
Magnetic noise can be reduced by
increasing distance between cable
and offending power cable and
screening the cable
Screening
Communicati
on Cable
Prevent Noise Interface
Surge Protection
Lighting Protection
Control Cable
Provide Circuit Isolation
Prevent Noise Interface
Surge Protection
Contain Intelligence
High Voltage
Cable
Prevent Corona
Surge Protection
Fault Path Provision
Shield
Electro Static Screen (Grounded at one end)
Metal Tape
A flat Metal Tape
applied with
overlap around
pairs cable core or
inner jacket.Tape,
Al or Cu 75μm
thick
Metal Tape
with Drain
Wire
Copper
Drain Wire
Metal
Laminate
and Drain
Wire
A flat polyester
supported foil tape,
applied with
overlap, around
pairs, triples, etc.,
cable core, or inner
jacket. A drain wire
is normally used
with this type of
shield for ease of
terminating.
Conducting
Plastic and
Drain Wire
Drain Wire
& Semi
conducting
PVC or PE
Sheath
Metal
Braid
A double serving of
uninsulated wires
interlocking in a two
over-two under
pattern. The second
serving is applied in
the reverse direction
of the first
Magnetic Screen (Grounded at both ends)
Copper
Tapes
Copper
Tape
overlap
intrinsic
screening
factor 0.95
Copper
and Steel
Tapes
Cu and Mild
Steel tape
Intrinsic
screening
factor 0.9
Steel Tape
Armored
Cable
Lead or
Moisture
Sheath with
two layers
of Steel
Armour
tape, IS
factor 0.4
to 0.5
Aluminum
and Steel
Tape
Screen
Moisture
barrier, Al
wire/strip,
two layers
of steel
tape, IS
factor 0.06

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Screening
■ Cross-talk from adjacent pairs or triples;
■ Interference induced by external source
Aluminum /polyester tape with a tinned
copper drain wire, the most popular
construction. Aluminum /polyester or
copper/polyester tapes normally have a total
thickness from 25 to 100 μm, according to
standards and are wrapped with an overlap >
125% to assure a full coverage even in case
of bending.
Bare copper braid for electromagnetic
interference or when the cable is subject to
movements.Tinned copper braid for
electromagnetic interference in presence of
corrosive atmosphere or high temperature.
Copper braid normally has a coverage from
80% to 95%. This type of screen presents a
lower electrical resistance, a very good
protection also to electromagnetic noises and
a higher mechanical resistance compared to
aluminum /polyester tape.
Screening
Type
Overlap
Coverage
Isolation
In continuous contact with metallic side there is
a drain wire, normally tinned copper, 0.5 sq
mm, stranded or solid. Screens can be applied
to each pair/triples (individual screen) and/or
on the bundle of the cable (overall screen).

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Basic Design BS 5308 or EN 50288 - 7
Armoring
Metallic armor are used when cables have to be installed
direct buried, or if mechanical protection is required.
■ Required tensile load
■ Expected pressure on cable during service
■ Protection against rodent
■ Protection against accidental damage
■ Minimum required bending radius.
SWA: Single layer of galvanized steel wires, with diameters
according to relevant standards, coverage min. 90%. This
armor assures a very good mechanical protection and tensile
strength. An additional counter spiral tape increases solidity, if
required.
GSWB: Galvanized steel wire braid, diameter of wire: 0.20 –
0.25 – 0.30 – 0.40 mm, with coverage of > 80%. It assures a
good mechanical resistance, allowing a lower bending radius
compared to other armor. It is preferable when there is
movement or vibration. For special application is possible to
use stainless steel, tinned copper or special alloy wires.
Armoring
Direction
BS EN 1027
Coverage
Application
GSTA: Galvanized steel tape armor, composed by two tapes
with overlapped edge; thickness of each tape: 0.20 – 0.30 –
0.40 mm, according to cable diameter. It grants a coverage >
100%. Very good crush resistance, but fair tensile strength.
Brass tape of minimum thickness 0.075 mm can be used for
special applications.
GSFA: Galvanized steel flat armor. It is composed by flat
wire of thickness 0.6 mm or 0.8 mm, it is similar to SWA, but
with higher mechanical protection.

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Sheath
Many compounds can be used as
internal/external protection of cables.
Working condition need to be considered for
the right choice. PVC, PE and LSZH are the
most popular materials, but we have to
consider that different grades are available to
meet specific working conditions. Anyway the
following conditions have to be evaluated:
 Type of installation (indoor/outdoor, direct
buried…)
 Possible presence of humidity, oil, chemicals…
 Behavior in case of a fire (fire propagation, fire
resistance, emission of gases and smoke…)
 Range of temperature
 UV resistance in case of sun exposure
Screening
Type
Wall Thickness
Temperature
Color

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Basic Design BS 5308 or EN 50288 - 7
Protection
Protection
In addition to mechanical protections, special
protections can be considered for specific
installations
Moisture barrier
If moisture barrier is specified it shall be applied over
the total cabling of elements and is possible to
choose two alternatives:
Water swellable tapes
Laminated sheath, consisting of a longitudinal
overlapped metallic foil, bonded to an extruded
sheath.
Lead Sheath
It is applied between two other sheaths and is the
best protection against aggressive chemicals. This is
an expensive solution, increases weight and bending
radius. It presents poor vibration resistance and
normally an armor is required to protect it from
crushing.
Cable
Protection
Moisture Barrier
High Pack
It is an alternative to Lead Sheath and is
composed by a longitudinal overlapped
aluminum copolimer coated tape bonded to
HDPE jacket and additional special alloy of
polyamide/polypropylene sheath.
■ Excellent protection against corrosion
and humidity.
■ Excellent impact resistance that in some
cases prevents the use of the armor. This
protection has a lower weight compared to
lead sheath, cables have a smaller
diameter, with a reduction of costs. Hi-Pack
is the right choice to protect the
environment.

14. Thank you
Some tables below

15. 15
Materials
Insulation
Sheath
Temp.Low
Temp.High
Abrasion
resistance
Oilresistance
Solvent
Resistance
Water
Resistance
Nuclear
radiation
resistance
Flame
retardancy
Flexibility
PVC -40 +105 3 3 2 3 2 3 3
Polyethylene -40 +80 3 2 3 4 2 1 2
Polypropylene -40 +105 4 4 4 4 2 1 2
Nylon -70 +120 4 4 4 2 2 1 2
Polyurethane -40 +80 4 4 2 3 3 3 3
XLPE -60 +90 2 3 3 3 2 1 2
Fluoropolymer FEP -80 +205 2 4 4 4 1 4 2
FP PTFE -80 +260 2 4 4 4 1 4 2
FP PFA -80 +260 2 4 4 4 1 4 2
FP MFA -80 +240 2 4 4 4 1 4 2
FP ETFE -80 +155 2 4 4 4 1 4 2
4. Very Good ; 3. Good ; 2. Fair ; 1. PoorCan be used

16. 16
Materials
Insulation
Sheath
Temp.Low
Temp.High
Abrasion
resistance
Oilresistance
Solvent
Resistance
Water
Resistance
Nuclear
radiation
resistance
Flame
retardancy
Flexibility
FP ECTFE -60 +160 3 4 4 4 3 4 1
Hytrel -40 +80 3 4 4 3 1 1 2
Peek -60 +250 2 4 4 4 4 4 1
Kapton -75 +200 4 4 4 4 4 4 1
Technopolymer
LSZH
-30 +90 2 3 2 4 4 3 2
G10 -40 +90 2 2 1 3 3 3 3
Silicone Rubber -60 +200 2 2 1 3 3 3 4
Thermoplastic
Rubber
-55 +125 4 3 2 3 1 3 4
Neoprene -40 +90 4 3 2 3 2 3 4
EPR -50 +90 3 2 1 3 3 1 3
LSZH -30 +90 2 3 2 3 3 3 2
4. Very Good ; 3. Good ; 2. Fair ; 1. PoorCan be used

17. Insulation and Jacket Materials Properties
Properties
P= Poor
F= Fair
G= Good
E= Excellent
O = Outstanding
The ratings are based on average
performance of general purpose
compounds. Any given property can
usually be improved by the use of
selective compounding.
Thermoplastic Thermoset
PVC
LowDensityPolyethylene
CellularPolyethylene
High-DensityPolyethylene
Polypropylene
CellularPolypropylene
Polyurethane
Nylon
CPE(ChlorinatedPolyethylene)
PremiumgradePVC
FEP
Tefzel(ETFE)
PTFETeflon
Sole/Kynar
Halar
Neoprene
ChlorosulfonatedPolyethylene
EthylenePropyleneRubber(EP,
EPR,EPDM)
XLPE
CPE(ChlorinatedPolyethylene)
SiliconRubber
Oxidation resistance E E E E E E E E E E O E O O O G E E E E E
Heat resistance G-E G G E E E G E E G-E O E O O O G E E G E O
Oil resistance F G-E G G-E F F E E E F O O E E-O E G G P G G-E F-G
Low-temperature flexibility P-G E E E P P G G E P-G O E O O O F-G F G-E O F O
Weather, Sun resistance G-E E E E E E G E E G O E O E-O O G E E G E O
Ozone resistance E E E E E E E E E E E E O E E E E G G-E O
Abrasion resistance F-G G F E F-G F-G O E E-O F-G E E O E E G G F-G G-E P
Electrical Properties F-G E E E E E P P E G E E E G-E E G E E F-G G
Flame resistance E P P P P P P P E E O G E E E-O G P P G F-G
Nuclear radiation resistance F G-E G G-E F F F G F-G O P-G E P E E F-G E G E G E
Water resistance F-G E E E E E P-G P-F O F E E E E E E G-E G-E G-E G-E
Acid resistance G-E G-E G-E E E E F P-E E G E E E G-E E E G-E G-E E F-G
Alkali resistance G-E G-E G-E E E E F E E G E E E E E E G-E G-E E F-G
Gasoline, Kerosene, etc resistance P G-E G G-E P-F P P-G G E P E E E E E G F P F F P-F
Benzol, toluol etc resistance P-F P P P P-F P P-G G G-E P-F E E E G-E E P-F F F F F P
Degreaser solvents resistance P-F G G G P P P-G G E P-F E E E G E P P-F P F P P-G
Alcohol resistance G-E E E E E E P-G P E G E E E E E F G P E G-E G
Underground Burial P-G G F E E F G P E-O P E E E E E G-E E E E E G
Percentage Oxygen (Typical) 23-42 21 18-30 21 21 17 21 24-29 28-36 38-42 30-32 93 43-45 55 32 34 21 30-40 28-36 21
Dielectric Constant ( Typical) 3.6 - 6 2.3 1.5 2.3 2.2-2.3 2.2-2.3 4-7 3.2-5 12 4.5-6.5 2.6 2.1 7-9 2.6 9-10 8-10 3-3.2 3.4 -5 12 3-4
Thermal Characteristics - Deg C (Min) -30 -50 -40 -50 -10 -55 -40 -20 -100 -190 -40 -30 -30 -30 -40 -60
Thermal Characteristics - Deg C (max) 70 100 70 100 100 80 100 105 150 260 135 80 90 90 100 180

18. Halogen Content in Typical Insulation and Jacket/Sheath Materials
Material Application Voltage Weight %
PE insulation or Jacket <0.02
XLP insulation 600 V <0.02
XLP insulation 5-35KV <0.02
EPR insulation 5-35KV <0.02
Polyurethane jacket <0.02
EVA jacket <0.02
XLP insulation 600 V 7–13
FR-EPR insulation 9–14
CSPE (insulation grade) 13–16
FR-XLP insulation 11–17
CSPE jacket 16–26
Neoprene jacket 16–18
CPE jacket 14–28
CSPE jacket 18–33
PVC jacket 22–29