The scope was to model two adjacent kiosks in an industrial brownfield development. The client possessed standards for single kiosk type installation however there was no standard or guideline addressing two adjacent kiosks with a single encompassing earth grid.
The design team in Peracon use CDEGS and Streets earth modelling applications. CDEGS for the more complex installations with the flexibility to cater for complex earth grids. The Streets software that allows modelling for MEN impedance with an easy-to-use interface to model fault current split.
Peracon evaluated the strength and limitations of each software package against the corresponding requirements this earthing evaluation will require. Following this Peracon developed a non-traditional approach to this complex situation using a combination of CDEGS and Streets to:
โข Calculate the fault current split
โข Model the EPR, step and touch voltage
โข Assess clearance requirements against AS2067, AS3835 and AS4853, EG(0)
โข Confirm the compliance of the proposed new earth arrangement
โข Determine the type of earth system to be applied; common or separate This paper will explore the journey including design philosophy, design principles applied, assumptions made, on site challenges, that resulted in a client approved design.