This simulator models touch potential — the voltage difference between bonded, accessible metal equipment and the earth beneath a person's feet during a ground fault — using an explicitly simplified, homogeneous-soil hemispherical electrode model. Inject a timed ground fault, adjust soil resistivity, electrode geometry, equipment bond resistance and body/contact resistance, and watch ground potential rise, the equipment bond drop and the resulting touch voltage develop and clear.
• A real-time 3D scene of the current injection point, buried ground electrode (hemisphere), the surface-potential field, bonded accessible equipment and the earth-at-feet measurement position, with home view, focus-selected-part, toggleable enclosure cutaway, auto-rotate, expand and show/hide labels controls. • A Grounding workbench tab with a labeled parts index (fault injection, buried ground electrode, surface potential field, bonded accessible metal, measurement positions, remote return reference) and click-to-inspect component callouts. • Fault, earth & measurement fixtures: applied ground-fault current (100–10,000 A), uniform soil resistivity (10–1,000 Ω·m), equivalent electrode radius (0.5–30 m), foot position from injection center (1–30 m), equipment bond resistance (0–0.1 Ω), assumed body resistance (500–3,000 Ω), resistance of each foot contact (0–5,000 Ω) and fault duration (0.1–2 s). • Playback controls: pause/resume, single step, larger step, and four playback speeds (0.1×, 1×, 10×, 60× laboratory speed), plus an 'Apply timed ground fault' / 'Clear fault now' action pair. • A Potential-profile analysis tab with two live charts, the underlying model equations (Rg, Vsurface(r), GPR, Vtouch, Ibody) and snapshot measurement readouts covering bonded equipment potential, earth at feet, ground potential rise and equipment bond drop. • An Experiments tab with four guided fixtures (reference fault, higher soil resistivity, changed geometry, contact/return effect) and a Model verification bench that runs independent deterministic checks against a fresh model without disturbing your live experiment, plus a timestamped event log and a copyable trial report. • A Learn & assess tab with guided lessons, a knowledge-check quiz with reset, and a written model-scope statement with an OSHA reference link.
During a ground fault, current flowing through resistive soil raises the local grounding system's potential relative to remote earth (ground potential rise, GPR). Metal equipment bonded to that grounding system follows GPR plus its own modeled bond-conductor voltage drop, so the equipment can sit well above remote-earth potential even though it is properly bonded.
Touch voltage compares that bonded-equipment potential against the earth potential directly beneath a person's feet: Vtouch = |GPR + If·Rbond − V(r)|. Because the person's feet are typically closer to the fault than the equipment's bonding point, the earth-at-feet potential differs from the equipment potential — and a low-impedance bond does not by itself force that difference to zero.
The simulator converts open-circuit touch voltage into an assumed body-circuit current using Ibody = Vtouch / (Rbody + Rfoot/2), reflecting the parallel-feet touch path rather than the series two-foot step path. Increasing foot-contact resistance lowers the calculated body current without changing the open-circuit touch voltage itself.
This is a homogeneous, quasi-static hemispherical-earth model with a constant-potential interior — it does not represent a solved IEEE 80 ground-grid calculation, real mesh gradients, multilayer soils, transferred potentials or physiological injury thresholds, and it makes no safe/unsafe classification. A site-specific engineering grounding and exposure assessment is required for any real installation.
Touch potential is the voltage difference between bonded, accessible metal equipment and the earth beneath a person's feet during a ground fault. It exists because ground potential rise plus the equipment's bond-conductor drop can differ from the surface potential at the person's standing location, even though the equipment is bonded to the grounding system.
No. Bonding controls the equipment's potential relative to the grounding system, but that potential still rises with ground potential rise (GPR) plus the bond conductor's own voltage drop during a fault. Touch voltage compares that equipment potential to the earth potential at the person's feet, which is not automatically the same value.
Increasing bond resistance increases the equipment bond drop (If·Rbond), which adds directly to the touch voltage term Vtouch = |GPR + If·Rbond − V(r)|. A higher-resistance bond connection can therefore increase the exposure voltage at the equipment even though the equipment is still technically bonded.
No. This is a homogeneous, quasi-static hemispherical-earth teaching model with a constant-potential interior — it omits real ground-mesh gradients, multilayer soils, transferred potentials and exposure variability, and it makes no safe/unsafe determination. A site-specific IEEE 80 grounding and exposure analysis is required for any real installation.