Resistance equation for multiple horizontal anode groundbed

Until recently, there was not a resistance equation for multiple horizontal anode groundbeds.  In the case when the anodes are in the same coke breeze bed, the groundbed resistance can be calculated with the Dwight’s single horizontal anode equation.
In the case of several horizontal anodes in an individual coke bed, an interference factor between anodes, some times called the crowed factor, is used.  The interference factor is derived from Sunde’s vertical resistance equation for multiple anodes.
This paper presents two general equations for horizontal anode groundbeds, with the anodes in individual coke breeze beds.  The first case describes anodes that are in a parallel configuration, while the second one is for when anodes are placed in the same line, but still in an individual coke breeze bed.
An analysis of the Sunde’s equation for multiple electrodes in horizontal configurations is done in order to show that this equation cannot be used in the case of typical cathodic protection designs.
This paper offers a more accurate approach to the horizontal anode groundbed design and helps in the understanding of the general theory behind the groundbed resistance equations.