Step Potential Higher than Touch Potential ? 3

[Romanko]

I have recently been advised by the Electrical Approval Authority, that the Step Potentials within the Electrical Substation could exceed the Touch Potentials.
The gentleman quoted a journal paper by Dr Dawalibi that is also referenced from the IEEE 80 standard.

Has any body heard of it and/or encountered it, or can give me a quick pointer?

thankfully
ROMANKO

 

[jghrist]

In most substations, there isn't a lot of area where there is no equipment or plans for future equipment. I generally ensure that there are safe touch potentials throughout the fenced area and 3 feet outside the fenced area. This does not mean evenly spaced grids. Closer spacing around the perimeter and at corners is usually a more efficient use of copper because potentials will be higher around the perimeter if the grids are evenly spaced. Spacing in the center can be larger, but consideration has to be given to keeping the grid conductors close to equipment to reduce the length of ground stingers that connect the equipment and support structures to the grid.