Hot Line Tag is a North American distribution network terminology for a device state when used for live line work. This effectively blocks auto-reclosing too, as self-initiated. A1-1. 1 The Guidelines are applicable to insulating pole live line working and insulating glove live line working performed on 10 kV (20 kV) distribution lines at an altitude of 1,000 m and below. Transmission lines operate at voltage levels from 69kV to 765kV, and are ideally tightly interconnected for reliable operation. Factors like. In electrical engineering, live-line working, also known as hotline maintenance, is the maintenance of electrical equipment, often operating at high voltage, while the equipment is energised. As the utility business primary directive is to maintain power reliability and uptime for customers, engineers have devised many risk mitigation techniques to. In order for utilities to provide continuity of service, live line maintenance on energized distribution and transmission lines is required. The survey was issued in 2000 and responses were received through 2001.