NEC Grounding
Article 250 covers far more than the grounding electrode conductor sizing table — a broader map of what it actually contains.
NEC Article 250 — Grounding and Bonding — is one of the code's longest and most comprehensive articles, and Table 250.66's GEC sizing (covered in a dedicated article) is only one specific piece of it.
| Topic area | General scope |
|---|---|
| System grounding | How and when the electrical system itself must be grounded, and the specific connection points |
| Equipment grounding | Bonding requirements for enclosures, raceways, and equipment — distinct from the grounding electrode conductor covered in the dedicated GEC article |
| Bonding | Ensuring metal parts are electrically connected together to maintain a low-impedance fault path and equalize potential |
| Grounding electrodes | What qualifies as a grounding electrode (ground rods, concrete-encased electrodes, metal water piping under specific conditions) and how they must be combined when more than one is present |
Treating "grounding" as synonymous with "look up the GEC size in Table 250.66" misses most of what a compliant grounding and bonding system actually requires — the GEC is one output of a much larger set of requirements.
OhmWorks' NEC Grounding calculator focuses specifically on GEC sizing per Table 250.66 — the rest of Article 250's requirements need separate, direct review against the full article.
Engr. Jason Morales — Founder, SolarEnergyPH & OhmWorks