Home » English riddles » General Subjects » Electrical question no.18 – Electrical HV Transmission lines » Reply To: Electrical question no.18 – Electrical HV Transmission lines Reply To: Electrical question no.18 – Electrical HV Transmission lines 2021-08-03 at 11:08 am #1593 Dr.D It is a housing that covers a vibration damper to reduced wind driven vibration of the line.