Earthing & CDEGS Study
Earth-grid design with step / touch-potential analysis.
A safe earthing system
NEWATT designs the earth grid and verifies step and touch potentials against safety limits using soil-resistivity data.
Study scope
Earth-grid design
Earth grid, conductor and rod design is developed from fault current, clearing time and soil resistivity data, sizing the grid to keep step and touch potentials within safe limits while achieving the grid resistance the system's earthing philosophy requires.
Soil resistivity
Multi-layer soil modelling from site resistivity testing underpins the earthing design, since treating genuinely layered soil as uniform can significantly misstate grid performance, and we build the layered model directly from Wenner or Schlumberger survey data rather than assuming uniform conditions.
Step & touch
Step and touch potential verification confirms safe voltage exposure at every point a person could contact equipment or ground during a fault, checked against IEEE 80 safe limits for the site's specific fault clearing time and soil conditions.
Grid resistance
Grid resistance and ground potential rise are calculated from the grid design and soil model, confirming the earthing system achieves the resistance target the protection and safety design requires, and checking GPR doesn't create a hazard at the site boundary or nearby structures.
How we deliver
Standards
Earthing design follows IEEE 80 for safety-voltage methodology and IEC 60364 where the project's regional requirements call for it, with the governing standard for each aspect of the design documented explicitly.
Software
Detailed earthing analysis is performed in CDEGS or the earthing modules within ETAP, giving accurate results for complex soil layering, nearby structures or high fault currents that simplified hand-calculation methods can't represent reliably.
Outcomes
The study delivers an earthing design and safety report documenting grid layout, conductor sizing, calculated step and touch potentials against the safe limit, and any supplementary grounding needed to bring the site within safe limits.