Safe clearances and protection against shocks during live-line work

An equation, based on the highest switching surges and including safety factors, is developed for the limit of approach to live parts of transmission lines. The effect of temporary protective gaps is shown, and the mechanism of shocks experienced by linemen during loose contact with a tower is discussed. Such shocks, although harmless, are annoying and can be avoided by the use of conducting shoes Live-line maintenance is performed by many utilities with a high degree of safety at all voltage levels now used. It will be expedient to extend this practice to lines operating at voltages of 460 kv and over, but in so doing it seems advisable to analyze the possible hazards which may be encountered and to see how the present degree of safety can be maintained.