Ground Potential Rise Screen (IEEE 80)
The yard-voltage side of step-touch-voltage: GPR = grid_current x grid_resistance, screened against the tolerable touch voltage. The IEEE 80 shortcut - a GPR at or below the tolerable touch means no yard point can exceed it, so no mesh/step analysis is needed. A 200-A grid current on a 0.5-ohm grid rises just 100 V (passes a 200-V limit outright); a 5,000-A fault on a 1-ohm grid rises 5,000 V (25x the limit, full mesh/step study required). A screen, not a grounding design.
Formula and source
gpr_v = grid_current_a x grid_resistance_ohm; safe_by_gpr = tolerable_touch_v > 0 AND gpr_v <= tolerable_touch_v.
IEEE Std 80 ground potential rise, by name.
Audience
This tile is built for electricians and the adjacent professions in the Electrical group. The interactive calculator runs entirely in your browser. No account, no fee, no advertising, no tracking.
Related tools
Posture
Rough Logic answers the math question the working professional asks on the job. The site is a calm, fast, ad-free, account-free, ever-free reference. It does not interpret code. It does not replace the licensed professional. It does not store your inputs. The Authority Having Jurisdiction governs all installations and inspections.