In applications where
cables may be subjected to attack from oils, solvents,
gases or other chemicals, designers and installers
of critical cabling systems have historically
relied upon using conventional lead-sheathed
cable to provide maximum protection. However,
the use of lead sheathed cable is often unsatisfactory
due to its weight, large bending radius and
cost.
For applications prone to
hydrocarbon attack and moisture penetration,
especially relevant to the on-shore oil, gas
and petrochemical industries, Draka has developed
a new generation of non-permeable cables, utilising
a combination of modern materials allied to
novel production techniques. This new Hishield®
cabling system provides excellent resistance
to hydrocarbons, its performance being similar
to lead alloy, but with significant advantages.
Cable weight is
reduced by up to 70%
Overall diameter
is reduced by up to 20%
Bending radius is
reduced by up to 25%
Termination time
is reduced by up to 50%
Less hazardous to
health
In addition to mechanical
abuse and attack by aggressive hydrocarbons,
cables carrying important data signals and communications
may in industrial environments also be subject
to Electro-Magnetic Interference (EMI). Draka
has recognised this problem and has, therefore,
also included an effective metallic screening
layer in all Hishield® cables.
Chemical Attack
The often unseen, yet persistent assault
from aggressive liquid and air borne chemicals
can be a major cause of cable failure.
Chemicals can
effect the cable in a variety of ways:
By attacking the
sheathing and insulating materials
leading to embrittlement and cracking,
or causing swelling associated with
a dramatic reduction in mechanical
strength and physical properties.
In both cases premature cable failure
is the result.
By disrupting the
electrical performance of the cable
leading to corruption of transmitted
information and ultimate electrical
breakdown.
Chemical
attack is reduced by the introduction
of the Hishield® protective system.
Moisture
Penetration
The additional threat of moisture penetration
to the cable core assembly may result
in the corruption of transmitted information.
Moisture can
cause corruption of the signal by:
Increasing the capacitance
and deterioration of other electrical
properties.
Increasing the mismatch
of information due to the changing
characteristic impedance.
Moisture penetration is reduced by the
introduction of the Hishield® system.
Electro-Magnetic
Interference (EMI)
This increasingly common form of electrical
disturbance occurs when faulty equipment* switching or external interference causes
spikes or electrical noise to appear in
the power supply. This electrical distortion
can effect vital transmission, leading
to corrupted or even lost data. Although
filters and suppression products are available
to reduce the likelihood of EMI, additional
protection is recommended to minimise
its damaging effects and to help maintain
signals free from electro-magnetic interference.
*some
correctly functioning equipment also gives
rise to EMI.
The Hishield®
system reduces the effect of electro-magnetic
interference on the cable.
Draka’s Hishield®
advanced cabling system can be applied
to most types of (BS 5308) instrumentation
and control cables, offering non-hazardous
protection from chemicals, water, solvents
and also effective screening against radio
frequency interference (RFI) and EMI.
The same protective sheath combination
can be applied to most types of control
and light power cables.
Technical Data for
Cables Complying to BS 5308
POLYETHYLENE
PVC
Maximum
conductor operating temp:
+ 65°C.
+ 65°C.
Minimum
ambient temp:
-20°C after installation and only
when cable is in fixed position.
-20°C after installation and only
when cable is in fixed position.
Maximum
working voltage:
300/500V r.m.s.
300/500V r.m.s.
Test
voltage:
1000V r.m.s. between conductors and
between conductors and screen/armour.
1000V r.m.s. between conductors and
between conductors and screen/armour.
Maximum
d.c. conductor resistance:
Conductor size
Ω/km at 20°C
0.5mm2 Class 1
36.8
0.5mm2 Class 5
39.7
1.0mm2 Class 1
18.4
1.5mm2 Class 2
12.3
Conductor size
Ω/km at 20°C
Multicore
Multipair
0.5mm2 Class 5
39.0
39.7
0.75mm2 Class 5
26.0
26.5
1.5mm2 Class 2
12.1
12.3
Minimum
insulation resistance:
Individual cores - 5000 MΩ/km
at 20°C.
Between individual screens - 1MΩ/km at 20°C.
Individual cores - 25
MΩ/km at 20°C.
Between individual screens - 1MΩ/km at 20°C.
Maximum
mutual capacitance at 1KHz:
Cables without individual pair screens,
0.5mm2 and 1.0mm2 - 75pF/m, 1.5mm2 - 85pF/m. All cables with individual pair screens and 1 or 2 pair
cables collectively screened, 115 pF/m, except 7/0.53mm (1.5mm2),
120 pF/m
Pair or adjacent cores - 250 pF/m
at 1KHz.
Maximum
capacitance unbalance:
250 pF/250m at 1KHz
Maximum
capacitance conductor to screen:
450 pF/m at 1KHz
Maximum
L/R ratio:
Conductor size
µH/Ω
0.5mm2
25
1.0mm2
25
1.5mm2
40
Conductor size
µH/Ω
0.5mm2
25
0.75mm2
25
1.5mm2
40
Minimum bending radius:
8 x overall diameter.
8 x overall diameter.
*Cables using
this composite sheath should not be connected
to a low impedance source i.e. the mains power
voltage supply.
Please refer to our BS
5308 catalogue for the core sizes and configurations.
The new HISHIELD system is also suitable for
applications requiring termite and rodent protection.
For further information on
specific applications please contact your local
sales office.
Typical
Construction
Plain
annealed copper conductor.
PVC/Low
Density Polyethylene/Cross-linked
Polyethylene (XLPE) insulation.
Individual
pair screen (optional).
Polyester
tape.
Tinned
soft copper drain wire.
Aluminium/Polymer
foil tape,
- Impermeable to moisture.
- Protection against EMI.
High
Density Polyethylene (HDPE) bedding,
- Resistant to inorganic chemicals.
Extruded
polyamide layer (Nylon),
- Resistant to organic chemicals.
Galvanised
steel wire armour.
HDPE/Fire
retardant PVC.
Download the individual data sheet for Hishield® cables
Download Cables Brochure to see the whole range of industrial cables by Draka
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