Resistance of large earth-electrode systems

In three earlier papers by the same author, methods have been suggested for the measurement of the resistance of large earth-electrode systems, which presents certain difficult problems. These methods are all based on certain assumptions, and it may be that, in practice, these assumptions are not fully justified, and so errors may occur. Again, each of these methods has its own advantages and disadvantages, and it is the purpose of this paper to summarise and compare the three methods and to determine the errors which may arise in certain cases where the basic assumptions are not fully justified. It is shown that the three methods can give equally accurate results, but that two of them are more reliable than the third. Also, that some departure from the basic assumptions does not cause serious error.