Variations in temperature always affect the electrical performance of a cable assembly; higher temperatures increase conductor resistivity, hence copper losses. Temperature variations can affect dielectric properties significantly, so that the dielectric is generally the temperature-limiting factor (temperature range for Polyethylene is -65 Cº to +80 ºC, PTFE is -75 ºC to +250 ºC). Solid Teflon cables are generally not recommended for extended applications above 150ºC. Splined and micro-porous cables improve the thermal limitations of the solid Teflon dielectric, but require larger bend radii.