GroundLoop: Earth Ground Test

GroundLoop is the grounding field companion for electrical engineers, contractors, and tower techs — fully offline, no account, no subscription.

SOIL RESISTIVITY
Enter Wenner four-pin or Schlumberger readings and get apparent resistivity per spacing instantly, with probe-depth correction, anomaly flags for layered soil, and a resistivity-vs-spacing curve you can read at the truck.

ELECTRODE ESTIMATES
Size a single rod, a multi-rod array, or a grid (Sverak screening formula) and compare against your target — 25 ohms (NEC 250.53), 5 ohms, or a custom spec. Every result shows the formula reference it came from.

FALL-OF-POTENTIAL TESTS
Enter your current-probe distance and GroundLoop lays out the 52/62/72% voltage-probe positions, then checks your three readings for a valid plateau — so a bad test gets caught in the field, not back at the office.

FIELD REPORTS
Export a clean PDF per site: resistivity tables, electrode estimates with formula references, fall-of-potential records, and date — ready for your project file.

FREE TO TRY
One site with every tool unlocked, reports watermarked. One-time purchase removes the watermark and the site limit. No subscription, ever.

GroundLoop is a field calculation and recording aid. It encodes textbook formulas with cited references (values pending professional-engineer review are labeled in-app); it is not a substitute for a licensed PE's design, the governing standard, or required field verification.