Grounding & Bonding System Visualizer

Visualize grounding and bonding current paths across service entrances, separately derived sources, generators, and UPS systems — with fault injection showing how grounding method and bonding connections control fault-current return paths.

AVAILABLEAUTOMATED CHECKS ONLYSTANDARDS-AWAREBEGINNERNECWHAT DO THESE STATUSES MEAN?

NEC • ART. 2504 SOURCE TYPES3 GROUNDING METHODSFAULT PATH ANIMATION

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Overview

Grounding and bonding are two distinct NEC concepts that are routinely confused, misapplied, and inadequately explained. This visualizer separates them visually by animating current paths through a configurable system: the grounded (neutral) conductor, the equipment grounding conductor (EGC), and the grounding electrode conductor (GEC) each appear distinctly, and injecting a ground fault shows which path carries fault current back to the source. Source types include utility service entrance, SDS (separately derived source) transformer, generator, and separately derived UPS. Grounding methods (solidly grounded, high-resistance grounded, ungrounded) and bonding connection location (at source, load-side/sub-panel, or both) are selectable, with real-time feedback on how each combination changes the fault-current path and NEC compliance. The Comparison tab places two configurations side by side. A Scenarios tab covers Normal Operation and Ground Fault at Load. The result is a tool that makes NEC Article 250 tangible rather than purely textual.

App preview

A live look at the app you'll launch — every control on the left drives the visualizations on the right in real time.

Inside the lab

Example data — not a real field report

Dashboard tab with source type, grounding method, and bonding controls — Dashboard · Pick source type (service, SDS, generator, UPS), grounding method (solid, HRG, ungrounded), and where bonding is landed — every change updates the one-line and current-path readouts live.

Path View animating fault-current return through neutral, EGC, and GEC — Path View · Inject a ground fault and watch which conductor actually carries the return current — grounded (neutral), EGC, and GEC are drawn distinctly so grounding vs. bonding stops being abstract.

Comparison tab with two grounding configurations side by side — Comparison · Put two configurations side by side — for example solidly grounded vs. HRG, or bonding at source vs. at the sub-panel — to see the code and behavior differences at a glance.

Scenarios tab with Normal Operation and Ground Fault at Load presets — Scenarios · Preloaded Normal Operation and Ground Fault at Load cases so you can jump straight to the failure modes that NEC 250 is written to control.

Learn tab with NEC Article 250 background and definitions — Learn · Plain-language background on Article 250 — grounding vs. bonding, main bonding jumper vs. system bonding jumper, and when 250.30 applies to separately derived sources.

What you'll do

01Distinguish between grounding (earth connection) and bonding (equipotential connection) as defined by NEC Article 250
02Trace the fault-current return path for a solidly grounded system versus an ungrounded or HRG system
03Identify where the system bonding jumper and main bonding jumper must be installed for each source type
04Explain how a separately derived source changes grounding requirements under NEC 250.30
05Evaluate the effect of grounding method (solid, HRG, ungrounded) on first-ground-fault behavior
06Identify NEC violations when bonding connections are placed in incorrect locations

Try a guided scenario

Trace a ground fault and see what happens when the bonding path is broken.

Grounding and bonding fundamentals · Electrical Foundations

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What this lab is not

Not a design document, stamped calculation, or approval record.
Not a substitute for engineering analysis by a licensed professional.
Not a reproduction of NEC tables — values are computed and cited, and you must verify against the code edition enforced in your jurisdiction.
Not connected to live equipment and not a safety device.

Calculation basis

References NEC. Results are computed from the entered inputs and cited back to the referencing clause or table number — no code text or table is reproduced verbatim.

Simplifying assumptions are stated in the lab itself; where a model is intentionally conceptual, the lab says so rather than implying study-grade accuracy.

Standards basis: Standards-aware. Validation state: Automated checks only (last checked 2026-08-15).