WCA November 2015

Standardisation of PV wires and cables 2001-2014 By Faruk Yeginsoy, Leoni Struder AG

Abstract This paper will show the evolution from the first German TUV Rheinland document 2Pfg1169/2001 to 2Pfg1990/2012 and the influence of this document to national standards in the USA, Japan and Europe as well as to the development of the standards Cenelec EN50618 and IEC62930. Furthermore it will give an insight to the necessary design, material combinations and production processes to comply with the above stated standards. In particular the challenge was to comply with multiple standards, as for example the combination of UL and TUV. An additional aspect will give an understanding to specific testing procedures of essential compound properties which have an impact on the expected very long operation time of PV wires. 1 Introduction Starting at the end of the last century the worldwide interest in renewable energy was encouraging the PV industry to grow significantly and this growth around the world was irresistible. At that time the construction of PV systems was an expensive and long-term investment. The investors did not know how to estimate the quality of modules, and customers were asking for the expected lifetime of PV modules and PV installations. There was a strong need for a third-party assessment of safety and quality. At this time the German TUV Rheinland started reviewing the safety and quality of photovoltaic modules with their own requirements. Very soon it was clear that the module quality and module safety was dependent on the components, but there was a lack of standards for components considering the requirements of PV application. This was the beginning of the standardisation of PV wires. 2 The beginning In 2001 the TUV Rheinland in Germany started testing PV modules and noticed many problems because of the cables.

Since no dedicated standard tests for these cables existed, the TUV Rheinland created their own standard. This was the birth of 2Pfg1169:2004. This first standard was based on IEC60245-4:1994 (Rubber insulated cables - rated voltages up to and including 450/750 V - Part 4: Cords and flexible cables). At that time H07RN-F was the most used cable (rubber 60ºC–90ºC). In this early stage of PV installations, nobody realised that the requirements on PV cables were much higher. 2.1 First wiring failures after a few years

❍ ❍ Figure 1 : Wiring failures caused by ozone and high temperatures

3 New requirements After numerous wiring failures the PV experts recognised that the requirements of the first Pfg 1169 /2004 had been too low. In 2006 a new experts group (German National Committee Working Group 411.2.3) started to work on a new version of the “Requirements for photovoltaic cables”. In the first part of the work, it was a joined group of module and cable experts. The focus was now on the period of use of PV wires. The working group was principally involved in following questions: • How can we predict the lifetime of a cable? • How many years does the lifetime of a cable have to be? • How is ageing of cables to be understood? • How can we test the ageing process?

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Wire & Cable ASIA – November/December 2015