Electricity + Control October 2015

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.

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.

take note

Jennifer Lehmann is employed by The Lapp Group. Enquiries: Alan Liebenberg. Lapp Southern Africa. Tel. 011 201 3200 or email Alan.Liebenberg@lappgroup.co.za

Conclusion With its properties, the new fire-protection cable made from PUR is suitable for buses and many other applications where people need to

Electricity+Control October ‘15

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