A third test was conducted on contaminated insulators. Firstly, they were flashed over, then washed, then flashed over again. During the process the voltage was noted when the second flashover occurred, thus establishing the effectiveness of the “washing”. An important note to add is that most of the insulators obtained full insulation ability.
The importance of having clean insulators stems in the issue of avoiding power loss due to leakage along the insulator chain. The testers had established that 1 milliampere would be the maximum acceptable limit of leakage current. Through a series of trials the optimal water pressure and distance had been found. Further, the testers also determine that special equipment had to be used in the washing. Initially fire and gardening hoses had been used, but due to the inability at being able to achieve the optimal pressure, hoses with smaller orifices, allowing greater pressure, were developed.