Abstract: High category data cables, including Cat 7, Cat 8 and Small Form-factor Pluggable (SFP) cables, is a fast growing market segment of the cable industry. They have been developed to address the need for faster transmission rates, wider bandwidth and higher frequency usage (up to 40 GHz). These are twisted pairs of thin-wall insulated data cables wherein the insulation is physically foamed in order to achieve low signal attenuation while maintaining sufficient crush resistance for the application. High quality low loss foamed insulations require the ability to be manufactured with high expansion levels (>50%) exhibiting a fine and uniform cellular structure via a high speed gas injection process. In this work, we discuss foamed data cable insulation compounds with optimized range of nucleating agent technologies for superior cellular structure. We extend the previous studies to the performance of a REACH-compliant foaming nucleating agent technology to address concerns about widely used nucleating agents that are now classified as a Substance of Very High Concern (SVHC) by the European Chemicals Agency. The findings of this work will be of interest to those cable makers designing thin wall physical foamed insulation systems as well as those seeking to understand the science-based explanations for the behaviors observed with such nucleating agent systems.