Product guide

88
CABLE COMPOSITION
STANDARD CABLE.
This cable is based
on cores made from
7 strands of 0.2mm
annealed tinned copper
wire & is sheathed in
Type 1 PVC. These cables
are available in white
or brown.
LOW SMOKE & FUME CABLE. The standard
security cable can also be specified with a special
low emission PVC outer sheathing. Using this
sheathing, the compound oxygen index level is
greater than 32%.This means it will require more
than 32% of the volume of air to be oxygen for
it to catch fire. 'Normal' air contains around 19%
oxygen. The acid emission level is less than 10%.
A normal PVC sheathing compound would give
a figure of 20%.
14 STRAND CABLE. This is similar to the standard
cable except that each core is made up of
14 strands of 0.2mm cable. This gives a Nominal
conductor area of 0.44mm
2
. (This is often used
in areas where 0.5mm
2
wire is required).
SCREENED CABLE.
This uses the same cores
as standard cable. In
addition, an aluminium
foil is wrapped around
the cores. Screened
cable offers significant
advantages in situations
where RF interference
or spurious signals may lead to false alarms or
erosion of data. An earth drain wire is present
along the entire length of the cable providing
shield continuity and a convenient earthing
point at the control panel.
TWIN POWER & DATA. Two different conductor
types are used. A power pair (red/blue) is
provided in 16 strands x 0.2mm (0.5mm
2
) for
use where higher than normal current carrying
capacity or lower voltage drop is required.
The data cores consist of the standard
7 strands x 0.2mm tinned copper wire The data
cores are aluminium foil wrap screened (with
an earth drain wire) to give added protection
against induced transients that may be carried
via the power cores or outside influences.
TWISTED PAIR
CABLE. Each core
consists of 24 strands
of 0.2mm (0.75mm
2
)
copper wire. Each pair
of cores is twisted
and aluminium foil
wrap screened. A bare
7 strands x 0.2mm
earth drain wire is included. Twisted pair cable
is particularly useful for bus systems or for
installations requiring longer lengths of cabling
such as access control and CCTV.
Standard cable, Screened Twin power
Twisted pair
cable, low smoke & fume & data
Core Type: Annealed tin copper Annealed tin copper Copper
Strand Diameter 0.2mm 0.2mm 0.2mm
Strands per core 7 16 Power 7 Data 24
Nom
0.22mm
2
0.50mm
2 -
power
0.75mm
2
Conductor Area 0.22mm
2 -
data
Core Gauge 24 AWG 22 AWG 20 AWG
Insulation Thickness 0.3mm 0.4mm 0.3mm
Max. Operating
50v RMS 50v RMS 50v RMS
Voltage
Current Rating
1 AMP 3 AMP 4.5 AMP
Per Core @ 70˚C
Max Operating Temp 70˚C 70˚C 70˚C
Non Core Resistance
92 OHMS/KM 40 OHMS/KM 25 OHMS/KM
@ 20˚C
BS Standards BS4737, section 3.30 BS4737, section 3.30 BS4737, section 3.30
CABLE AT A GLANCE
CUT CABLE QUALITY, AND YOU CAN CUT
THE SYSTEM
There’s a cable standard for a reason – so don’t let the cable be the weakest link in
your system, warns ADI-GARDINER’s Intruder Product Manager Yvonne Butterworth.
Because if it is, a fault is very difficult to find – and very, very expensive to put right.
We are all quite correctly obsessed with meeting the tighter specifications for Intruder
systems and products, as most recently is the case with PD6662, yet we seem to ignore that
most universally used product in all installations, good old security cable, says Yvonne.
“Cable is cable, one is just as good as another” is one of the most repeated phrases I hear
among installers. Not only do I doubt that was ever true, but it is certainly not the case now!
There is a cable standard for a very good reason. BS4737 Part 3 is designed to approve a
cable with the minimum of resistance, and therefore ensure the effectiveness of the system
and reduce the incidence of false alarms due to signal drop.
Security cable might not appear to be the most sophisticated of components, yet its
characteristics are absolutely vital to the efficiency of the installation, and if inferior product
is used, it can easily be an unwelcome cause of false alarms.
BS4737 Part 3: Section 3.30: specification for components is the specification for PVC
insulated cables for interconnecting wiring, and specifies clearly on the conductor resistance
and construction along with PVC shrinkage, type and thickness, together with a minimum of
resistance. Should any of these parameters be compromised, this can jeopardise the system
integrity. Result – false alarms and expensive call-backs.
The recent dramatic rises in the price of copper, the main conductor used, coinciding with the
increasing system demands of PD6662, has put the quality of security cable firmly back on
the agenda within the industry.
There may inevitably be some cables offered which claim to meet BS but simply do not.
And there is also security cable on the market which may not claim compliance with BS4737,
but offers some small commercial advantage. The question is, is it worth the risk?
Lower costs for non BS cables are often reflected by the reduction in the amount of copper
used in the cable, and the absence of tinning, which is a process to assist good termination.
It can also be reflected in the conductor used, which may be a low grade copper, or an
alternative composite conductor material with significantly different characteristics.
The UK market has for many years taken the specification and availability of security cable
manufactured to BS4737 as the standard for all quality installations, but don’t take that for
granted, not in today’s competitive marketplace, warns Yvonne.
Don’t let the cable be the weakest link in your installation – always use cable manufactured
to the British Standard.
Cable Composition