Electricity + Control October 2015

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Jennifer Lehmann is employed by The Lapp Group.
Enquiries: Alan Liebenberg. Lapp Southern Africa. Tel. 011 201 3200 or email
take note
CABLES + CABLE ACCESSORIES
that has not been optimised would not pass this test – the fire would
spread like it does along a fuse, and it could set other cables and the
interior furnishings on fire before the bus has come to a halt and the
passengers have managed to evacuate.
Having said this, some buses have 140 metres of the company’s
new cable installed in them. This impressive length is found in the
first buses to be equipped with the new cable. They are going to a
European capital city that has ordered for than one hundred vehicles
of this type. The length of the cables varies and they can also be
considerably longer, for example with articulated buses, or if travel
buses are fitted with an entertainment system – as is the case in
long-haul aircraft which, for instance, provide every passenger with
a free choice of films. A luxury fitting such as this also dramatically
further increases the amount of data. A changeover to Ethernet cables
with fibre optic cables for even higher data rates is unlikely though,
particularly as the distances to be bridged in buses are not as great as
those in aeroplanes. In the buses which are currently being ordered,
only Ethernet cables with copper cores are used, and therefore Lapp
only provides buses with the copper variety of the optimised fire-
protection cable. Other cables such as low-frequency data network
cables and live cables can obtain the PUR sheath if there is sufficient
demand. After all, there will still be cable types in buses other than
Ethernet cables in the future. As long as they are installed in the
passenger compartment they must also comply with ECE-R 118.01.
Four months of 125 °C
Other than ECE-R 118.01, the most important standard for cables in
vehicles is DIN ISO 6722 with temperature class B, up to 100°C. For
temperature class B, the cable needs to be able to withstand a tem-
perature range of -40 to +100 °C℃ for a long period of time – normally
it is -20 to +90. This cable is even more heat-resistant. It has even
achieved the advanced special temperature class B (105). The stand-
ard specifies that the cable has been tested at a constant operation
temperature of 105 °C(for 3 000 hours). The short-term temperature
(for 240 hours) is specified as up to 130 °C. The safety buffer for ap-
plications in buses and cars is calculated very generously. What car
would experience 105 °C for four months? However, such properties
could be very sensible for other applications, such as photovoltaic
systems in the desert.
Conclusion
With its properties, the new fire-protection cable made from PUR is
suitable for buses and many other applications where people need to
be protected – such as cable for test benches in the motor industry.
A similar matter is its use in trams, which currently are not covered
in the standard. Trains have the highest requirements as it can take
some time for an ICE train to come to a halt, during which time the
fire must not have spread too far. The company is looking to develop
suitable connection solutions for this.
• Fire protection requirements for cables installed in buses
in Germany will be made stringent at the end of 2015.
• The new standard, ECE-R118.01, concerns cables installed
in the passenger compartment of the bus.
• This company has developed a cable that meets the
requirements of the standard.
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