EoW November 2011

technical article

Arrhenius Lutze Thermoflex Solar

Hours

Temperature in ºC

▲ ▲ Figure 4 : Long term thermal test results

▲ ▲ Figure 5 : The developed cable in different cross-sections

The determining factors in this application are external conditions, which do not depend on national laws and can depend only on local aspects. Therefore, a standard in the future will be established by international market acceptance. Due to the different requirements and philosophies in each individual standard, one cable cannot satisfy both standards at the same time. In order to meet these standards and not to compromise the performance of the cable, one type of cable is needed to satisfy the requirements of the German specification and another cable type is needed to satisfy the UL requirements. n 8 Acknowledgments We thank all our colleagues working in this project and supporting us in the preparation of this paper, namely Mrs Sari Gregson and Mr Helmuth Schubnell. Especially we thank the IWCS committee for giving us the opportunity to present this paper, and the IWCS staff for the outstanding support and coordination.

It is especially designed for outdoor use, which means direct sun radiation and air humidity, but due to the halogen free flame retardant cross-linked jacket material the cable can also be installed in dry and humid conditions indoors. A product life cycle of 25 years can be expected for this solar cable. Insulation and jacket are easily removable. All materials used in the cable are in conformance to European RoHS-directive. There are two versions available signed by ink-jet printing for positive and negative polarity. The dimension range is from 2.5mm 2 (overall diameter 4.5mm) up to 35mm 2 (overall diameter 11.0mm), other cross sections are available upon request. The described solar cable is named Lutze Thermoflex Solar XPE. It has passed all the described tests and was certified by the VDE testing and certification institute according to the discussed specification [2] . It is registered at VDE by Reg-No 8293. Another solar cable type using AWG conductor sizes has been developed according to UL 4703 [3] and is currently/ actually in the certification process. 7 Conclusions There are different standards for solar cables in different countries. The require- ments are very high, but they differ due to the various national philosophies in respect to safety and reliability issues as well as market and subvention aspects.

Friedrich Lütze GmbH & Co KG Bruckwiesenstrasse 17-19 D-71384 Weinstadt (Großheppach) 1224 (PLZ 71366) Tel : +49 715 160 530 Fax : +49 715 160 532 77 Email : automation@luetze.de Website : www.luetze.com Lutze Inc 13330 South Ridge Drive Charlotte, North Carolina 28273 USA Tel : +1 704 504 0222 Fax : +1 704 504 0223 Email : info@lutze.com Website : www.luetze.com Kabelwerke Villingen GmbH Am Krebsgraben 3/1 D-78048 Villingen – Schwenningen Tel : +49 772 120 617

9 References

[1] “Renewable Energy, Industry Overview”; Merrill Lynch, August 2007 [2] “Requirements for Cables for PV Systems”, DKE WG 411.2.3, February 2008 [3] “Photovoltaic Wire”, UL subject 4703, Underwriters Laboratories, June 2005

Fax : +49 772 120 617 90 Email : info@kwv-vs.de Website : www.kwv-vs.de

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EuroWire – November 2011