Earthing System Calculator

Step 1 & 2: Site Data Collection

Fault Current (kA):
Soil Resistivity (Ω-m): Sandy soil: 100 Clay soil: 50 Rock: 1000 Custom

Step 5: Detailed Design

Total Length of Grid (m):
Total Area of Grid (sq.m):
Conductor Size (sq.mm):
Burial Depth (m):
Number of Electrodes:
Electrode Length (m):
Electrode Diameter (m):
Electrode Material: Copper Copper-clad Steel Galvanized Steel

Step 6: Earthing Installation

Installation Method: Standard installation High-corrosion environment Special conditions

Step 7: Initial Testing

Test Method: Fall-of-Potential method Other methods
Test Conditions: Dry Average Wet

Step 8: Commissioning and Safety Verification

Standard Compliance: IEEE Std.80 ENA TS025 Other standards

Custom Touch Voltage Threshold (V):
Custom Step Voltage Threshold (V):

Calculation Results

Grid Resistance (Ω):

Step Voltage (V):

Touch Voltage (V):

Compliance:

Earthing System Design Report

Inputs

• Fault Current: kA
• Soil Resistivity: Ω-m
• Total Length of Grid: m
• Total Area of Grid: sq.m
• Conductor Size: sq.mm
• Burial Depth: m
• Number of Electrodes:
• Electrode Length: m
• Electrode Diameter: m
• Electrode Material:
• Installation Method:
• Test Method:
• Test Conditions:
• Standard Compliance:
• Touch Voltage Threshold: V
• Step Voltage Threshold: V

Calculations

Grid Resistance: Ω

Step Voltage: V

Touch Voltage: V

Compliance

Assumptions and Dependencies Per Step

• Step 1 & 2: Site Data Collection
  • Assumption: Fault current is uniformly distributed across the grid; soil resistivity is uniform across the site.
  • Dependency: Relies on accurate measurement of fault current (Step 1) and soil resistivity (Step 2). These measurements depend on external data sources (e.g., utility fault current data, soil resistivity tests) and site conditions (e.g., soil type, moisture).
  • External Factors: Availability of fault current data from the electrical network and soil resistivity test equipment.
• Step 3: Preliminary Design (Not Modeled)
  • Assumption: Initial grid layout is feasible within site constraints.
  • Dependency: Relies on Steps 1 and 2 for fault current and soil resistivity data to estimate initial grid size and layout. Also depends on Step 4 for safety criteria.
  • External Factors: Site layout constraints (e.g., available space for the grid).
• Step 4: Safety Criteria (Not Modeled)
  • Assumption: Fault clearing time is 0.5 seconds unless specified otherwise.
  • Dependency: Relies on Step 8 for standard selection (e.g., IEEE Std.80 or ENA TS025) to define touch and step voltage thresholds. Also depends on fault clearing time (not modeled) to set exposure duration.
  • External Factors: Regulatory requirements for safety thresholds.
• Step 5: Detailed Design
  • Assumption: Grid is a uniform mesh; electrodes are made of with negligible resistance variation due to material.
  • Dependency: Relies on Steps 1 and 2 for fault current and soil resistivity, and Step 3 for preliminary grid layout. The total length, area, and electrode details (new inputs) are used to calculate grid resistance.
  • External Factors: Availability of materials (e.g., conductors, electrodes) and site-specific constraints (e.g., depth limitations).
• Step 6: Earthing Installation
  • Assumption: Standard soil conditions unless high-corrosion or special methods are selected.
  • Dependency: Relies on Step 5 for the grid design (e.g., total length, burial depth, electrode details). The installation method (e.g., high-corrosion environment) adjusts the grid resistance.
  • External Factors: Environmental conditions (e.g., soil corrosivity, temperature) affecting installation.
• Step 7: Initial Testing
  • Assumption: Uniform soil moisture across the site based on test conditions (dry, average, wet).
  • Dependency: Relies on Steps 5 and 6 for the installed grid design and installation method. Test method (e.g., Fall-of-Potential) and conditions (e.g., wet, dry) adjust soil resistivity.
  • External Factors: Availability of testing equipment and weather conditions during testing.
• Step 8: Commissioning and Safety Verification
  • Assumption: Equipotential surfaces are created by the grid; step voltage measured at 1 m intervals, touch voltage at 1 m reach.
  • Dependency: Relies on Steps 5-7 for grid resistance, step voltage, and touch voltage calculations. Depends on Step 4 for safety criteria (thresholds) based on the selected standard.
  • External Factors: Compliance with local regulations and standards (e.g., IEEE Std.80, ENA TS025).
• Steps 9-15 (Not Modeled)
  • Step 9 (Final Testing): Depends on Step 8 for commissioning results and Step 7 for test methods.
  • Step 10 (Documentation): Depends on all previous steps for complete design and test data.
  • Step 11 (Maintenance Planning): Depends on Step 6 for installation method (e.g., corrosion considerations).
  • Step 12 (Periodic Testing): Depends on Step 7 for initial test methods and Step 11 for maintenance schedules.
  • Step 13 (System Upgrades): Depends on Steps 1-8 for baseline design and performance data.
  • Step 14 (Incident Investigation): Depends on Steps 1-12 for historical data if a fault occurs.
  • Step 15 (Decommissioning): Depends on Step 10 for documentation and Step 6 for installation details.