The application of novel composite core high temperature low sag (HTLS) conductor technologies comes with challenged for asset owners and contractors. Energyline have supported the type registration schemes for both Aluminium Conductor Composite Core (ACCC, CTC) and Aluminium Conductor Composite Reinforced (ACCR, 3M). Our involvement included developing the type test regime in the absence of a wholly applicable UK standard, test witnessing and factory audits. Our materials engineers input in understanding the design and manufacturing issues around the use of composite materials offered valuable insight.