Which cable insulation has superior resistance to heat deformation and environmental stress cracking?

Cross-linked Polyethylene (often referred to as XLPE) is recognized for its superior resistance to heat deformation and environmental stress cracking. This resistance is largely due to its molecular structure, which is altered through a cross-linking process that enhances its thermal and mechanical properties. XLPE can withstand higher temperatures compared to many other insulating materials, allowing it to maintain performance in hot environments without deformation. Additionally, because of its robust cross-linked structure, it exhibits excellent resistance to environmental factors such as moisture and chemicals, thus reducing the likelihood of cracking or deterioration over time.

In contrast, varnish-cambric, impregnated-paper, and polyvinyl chloride have different properties that make them less suitable in contexts where superior heat resistance and environmental toughness are required. Varnish-cambric is more suitable for lower-temperature applications and can be vulnerable to heat over extended periods. Impregnated-paper insulation has good dielectric strength but can experience issues with moisture and heat. Polyvinyl chloride, while versatile and commonly used, does not provide the same level of durability under high temperatures or harsh environmental conditions that XLPE offers. Thus, XLPE stands out as the best choice for applications requiring high performance in demanding environments.