OCPD-to-EGC selector
Find the Minimum Equipment Grounding Conductor Size
The selector uses the first listed OCPD threshold equal to or greater than the entered rating. It never rounds down or interpolates conductor sizes.
A 20 A device uses a baseline 12 AWG copper EGC. Enable JavaScript to look up another rating or material.
Limited reference excerpt
Common Equipment Grounding Conductor Sizes
Common OCPD thresholds are shown for quick reference. Use the selector for ratings not included in this limited excerpt.
Choose the first “not exceeding” threshold that is equal to or greater than the OCPD rating. Never select a lower row.
No displayed excerpt row matches this search. Use the lookup above or verify the complete table in the adopted NFPA 70 edition.
Scroll horizontally to view all material columns. Column headers remain visible while scrolling.
| Minimum wire-type EGC size | ||
|---|---|---|
| Copper | Aluminum or copper-clad aluminum | |
| 15 | 14 AWG | 12 AWG |
| 20 | 12 AWG | 10 AWG |
| 60 | 10 AWG | 8 AWG |
| 100 | 8 AWG | 6 AWG |
| 200 | 6 AWG | 4 AWG |
| 400 | 3 AWG | 1 AWG |
This excerpt is not a grounding electrode conductor table and does not replace special rules, installation restrictions, local amendments, or an effective ground-fault current path review. No standards-derived CSV or bulk table download is provided.
Equipment Grounding Conductor Chart Summary
- The baseline wire-type EGC lookup starts with the rating or setting of the upstream automatic overcurrent protective device—not normal load current.
- When the rating lies between listed values, use the first threshold that is equal to or greater than the rating.
- Copper and aluminum/copper-clad aluminum use separate source columns; do not substitute material by assuming a one-size step.
- The result is a table starting point. Installation conditions and other NEC provisions can require a different or larger conductor.
Equipment Grounding Conductor vs. Grounding Electrode Conductor
These conductors have different jobs and different sizing provisions. Similar names do not make their tables interchangeable.
| Conductor | Primary role | Do not size it with this lookup when… |
|---|---|---|
| Equipment grounding conductor (EGC) | Connects normally non-current-carrying metal parts into the effective ground-fault current path. | Special circuit or installation rules govern beyond the basic OCPD lookup. |
| Grounding electrode conductor (GEC) | Connects the grounded system or equipment to the grounding electrode system. | Always; GEC sizing is a separate task. |
| Grounded conductor (neutral) | Intentionally carries current under normal operating conditions where the circuit uses it. | Always; neutral sizing follows load and system rules. |
| Equipment bonding jumper | Connects portions of the equipment grounding path to maintain continuity. | The applicable bonding-jumper provision requires another basis. |
How to Use the OCPD Thresholds
- Identify the rating or setting of the automatic breaker or fuse ahead of the equipment.
- Select copper or aluminum/copper-clad aluminum for the wire-type EGC.
- Find the first source threshold not less than the OCPD rating.
- Read the conductor designation from the selected material column, then review the conditions that can modify the basic result.
Threshold example: A 50 A OCPD is above the 20 A row, so it advances to the 60 A threshold. The baseline result is 10 AWG copper or 8 AWG aluminum/copper-clad aluminum. It must not be rounded down to a smaller threshold.
When the Basic Table Lookup Is Not Enough
| Condition | Why it matters | Next check |
|---|---|---|
| Ungrounded conductors increased in size | The wire-type EGC can also require an increase. | Review the applicable 250.122 increased-size rule and circular-mil basis. |
| Motor circuit | The protective device may not be treated like an ordinary branch-circuit breaker. | Apply the motor-circuit provisions and the correct protective-device basis. |
| Multiple circuits in one wiring method | A common EGC is based on the largest applicable upstream device. | Identify every circuit and the largest governing OCPD. |
| Parallel raceways or cables | Each raceway or cable can have distinct conductor requirements. | Review the parallel-installation provisions before selecting a conductor. |
| Feeder tap | The supply-side device ahead of the tap can govern. | Apply the feeder-tap EGC rule and conductor-size ceiling. |
| Long or high-impedance fault path | The table minimum may not facilitate prompt protective-device operation. | Evaluate the effective ground-fault current path with qualified design and AHJ input. |
| Raceway or cable armor used as the EGC | This lookup returns wire-type conductor sizes only. | Verify the wiring method, listing, fittings, length limits, and continuity requirements. |
Worked Equipment Grounding Conductor Examples
20 A copper branch circuit
Given: A 20 A upstream OCPD and a copper wire-type EGC.
Method: The entered value exactly matches the 20 A threshold.
Baseline result: 12 AWG copper.
Check: Confirm the adopted edition, wiring method, termination, and that no special condition requires a larger conductor.
50 A rating between thresholds
Given: A 50 A upstream OCPD and a copper wire-type EGC.
Method: Advance to the first threshold not less than 50 A, which is 60 A.
Baseline result: 10 AWG copper.
Check: The result is only the table starting point; do not use the lookup alone for conductor-upsizing or special-circuit conditions.
Copper vs. Aluminum Equipment Grounding Conductors
The source provides separate conductor designations for copper and for aluminum or copper-clad aluminum. The relationship is not a universal one-AWG-step conversion, especially as designations transition from AWG to kcmil.
- Use the column matching the actual conductor material.
- Verify installation restrictions, environmental suitability, conductor protection, and minimum-size limitations.
- Confirm that terminals, connectors, and equipment are listed and identified for the conductor material and size.
- Do not infer current-carrying ampacity from the EGC designation; that is a separate conductor-sizing task.
NEC Edition, Local Adoption, and AHJ Review
Publication of a newer NEC edition does not mean it governs every project. State, local, and project requirements can use another edition or add amendments.
- Identify the code edition adopted at the project location.
- Check state and local amendments and project specifications.
- Follow listed equipment instructions and conductor-termination restrictions.
- Resolve unusual fault-path or installation questions with the designer and authority having jurisdiction.
Engineering References and Data Scope
2026 NEC wire-type equipment grounding conductor threshold lookup; OCPD ratings above 6000 A and non-wire grounding paths are excluded.
The interactive result is a transformed first-qualifying lookup. Only a limited common-rating excerpt is displayed; the complete copyrighted standards table is not reproduced or offered as a download.
- NFPA 70, National Electrical Code, 2026 edition — controlling source; Section 250.122 and Table 250.122.
- NFPA 70 Code-Making Panel 5 Second Draft preliminary report — official development-cycle cross-check for table values and related revisions; not a substitute for the final edition.
- NFPA NEC enforcement maps — state adoption overview; local adoption and amendments still require verification.
- NFPA Terms of Use — basis for limiting standards-derived reproduction and downloads.
Dataset and Source-Check Details
- Dataset label
- NFPA 70 (2026) Table 250.122 transformed lookup · v1.0
- Lookup rule
- First verified threshold greater than or equal to the entered OCPD rating
- Canonical units
- Amperes; exact AWG or kcmil conductor designation
- Valid range
- Greater than 0 A through 6000 A
- Missing values
- No interpolation, inferred conversion, or extrapolation
- Rights and download
- Copyrighted source; limited excerpt and single-result copy only; no CSV
- Verification date
- August 8, 2026
- Source check
- NFPA LiNK 2026 edition basis with official CMP-5 development-record cross-check
- Publisher
- Turn2Engineering
Equipment Grounding Conductor Size FAQs
The baseline table result is 12 AWG copper or 10 AWG aluminum/copper-clad aluminum. Confirm the locally adopted edition, permitted material, wiring method, and any condition requiring additional sizing.
The baseline Table 250.122 lookup uses the rating or setting of the upstream automatic overcurrent protective device, not normal load current.
Use the first listed threshold equal to or greater than the breaker or fuse rating. Never round down to a lower threshold.
No. An EGC forms part of the effective ground-fault current path for equipment, while a GEC connects to the grounding electrode system. They use different sizing provisions.
It can. Increasing ungrounded conductors for reasons other than specific ampacity adjustments can trigger additional 250.122 sizing review, so the basic OCPD lookup alone is not sufficient.
Use the Result as a Verified Starting Point
Start with the upstream OCPD rating, apply the first qualifying threshold, and keep the material column exact. Before specifying the conductor, confirm the adopted code, local amendments, effective fault path, wiring method, and every special condition that applies to the installation.