EoW November 2011

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EuroWire – November 2011 59
technical article
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 2.5mm2
(overall diameter 4.5mm) up to 35mm2
(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.
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.
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
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:
Website:
Lutze Inc
13330 South Ridge Drive
Charlotte, North Carolina 28273
USA
Tel: +1 704 504 0222
Fax: +1 704 504 0223
Email:
Website:
Kabelwerke Villingen GmbH
Am Krebsgraben 3/1
D-78048 Villingen – Schwenningen
Tel: +49 772 120 617
Fax: +49 772 120 617 90
Email:
Website:
▲ ▲ Figure 4: Long term thermal test results ▲ ▲ Figure 5: The developed cable in different cross-sections
Arrhenius Lutze Thermoflex Solar
Hours
Temperature in ºC