EuroWire Sept 2015

Technical article

6 The way to CENELEC and IEC 6.1 CENELEC In 2011 the German National Committee for PV wires and cables started to work out a revision of VDE-AR-E 2283-4 “Requirements for cables for PV systems”. The target was now to apply this draft as a new work item to CENELEC TC20. The main topics were: • Increasing the system voltage • Adapting test procedures to the new voltage level The result of this work is EN50618, which was published as a final draft in August 2014. 6.2 IEC In 2013 IEC adopted the draft EN50618 on request of IEC TC82 as a basic paper to start to work out an IEC standard for photovoltaic wires. This is now published as a committee draft IEC62930. The IEC draft is 95 per cent identical to EN50618. 6.2.1 The difference to EN50618 The main difference between EN 50618 and IEC 62930 is that in the IEC standard class two conductors are permitted for use for fixed installations. 7.1 Design There are no great differences in the design requirements of these new standards. Notice, however, the definition of black as preferred jacket colour. Minor changes are in the required layer thicknesses, which are slightly increased. 7.2 Test requirements Note that the material testing procedures have been widely changed by adapting IEC60811 ”Electric and optical fibre cables – Test methods for non-metallic materials”. • All test samples now have to be taken from finished cables • It is not permitted to conduct material tests on extruded tapes or moulded plates Paper courtesy of the 63 rd IWCS Technical Symposium, Providence, Rhode Island, USA, November 2014. 7 What is new in EN50618 and IEC 62930

Jacket Separator Insulation Conductor

▲ ▲ Figure 3 : Optimised design of a UL4703 and TUV1169 or TUV1169 wire

• Special

developed

polymer

as

separator • Separable layers which have been required by many customers (UL definition: “Thermoset insulation having a jacket”) • The difference of these two cable families are different layers thicknesses because the UL has a higher requirement for the insulation thickness • All compounds are thermoset (electron beam crosslinking) In 2013 the new requirement of the PV industry was to increase the system voltage to save cable cost and to increase the efficiency of the PV systems. The voltage rating of the first generation of PV wires according to TUV1169 was based on generic industrial cable standards. The standard voltage rating of low voltage cables in the CENELEC and IEC is U0/U = 600/1,000V AC or 900/1,500V DC. The nominal voltage rating of the new generation photovoltaic wire is U0/U = 1,000/1,000V AC or 1,500/1,500V DC. In the meantime TUV Rheinland developed 2Pfg1990/2012, which considers the new requirements. 5.2 New generation of UL4703 1,000V/ TUV 1,500V DC cables 5 The next step 5.1 New requirements

Two-layer jacket optimised for mechanical properties and flame retardance Two-layer insulation. Electrical properties and flame retardance Conductor

▲ ▲ Figure 4 : New design

The outstanding characteristics of this design are: • Four-layer extrusion in one pass (implicated by further increasing pricing pressure in the PV industry) • All compounds are thermoset (electron beam crosslinked) • Layers not separable (UL definition: “Composite insulation without a jacket”) • Approvals: UL (1,000V)/TUV (2Pfg1990)/ CSA 22.2 No. 271-11

Leoni Studer AG Business Unit Solar &Windpower Däniken Switzerland Tel : +41 799138728 Email : faruk.yeginsoy@leoni.com Website : www.leoni.com

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September 2015