WCA January 2018

Development and Qualification of a High Performance Zero Halogen Primary 90°C Wet Rated LV Insulation System By Mike E Slevin, David G Roberts, Allan P Marconi and James Freestone, SACO AEI Polymers

Abstract This paper describes the development and qualification of a moisture curable low smoke zero halogen (LSZH) cable insulation meeting UL 44 requirements. The overall development concept is outlined and data is presented on the final compound formulation showing that fire, electrical, mechanical and physical requirements have been comfortably exceeded. Industrial scale extrusion performance is also briefly reviewed. As LSZH cable types are deployed more widely in North America, this development should provide a solid platform for both new cable designs and future compound development. 1 Introduction There is growing interest at the global level in providing low smoke zero halogen (LSZH) solutions for all cable styles; this is particularly relevant in the built infrastructure with high human occupancy including mass transit, commercial buildings, airports and similar public places [1, 2] . The use of LSZH insulations (to 1,000V) is now well established in many international markets and supported by international and national standards. The initial considerations for a material to work as an insulation

in a low voltage (LV) system are the abilities to handle installation temperature (cold properties), to withstand the mechanical rigours of installation and finally to offer good mechanical and thermal ageing characteristics during service. Additionally, the insulation in a single conductor wire and cable defines the complete installed product and may need to offer good fluid (oil) resistance, which is an important challenge in developing a robust LSZH insulation. North American standards for LV insulations place an additional demand on LV insulation systems with requirements for long-term wet electrical stability. Cross-linked insulations offer important benefits in providing the highest level of protection in overload conditions and are often preferred against thermoplastic styles. Practical manufacturing approaches for cross-linking LSZH insulation systems include organic peroxide (CV) or electron beam systems entailing significant capital expense. A moisture cure approach offers important manufacturing efficiencies, avoids the high capital expenditure and affords significant manufacturing flexibility. The minimum fire performance for an insulation built to UL 44 is the FT2 horizontal burn; single insulated cores

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Wire & Cable ASIA – January/February 2018