You're on the right track with 250.68, but let's break down the specifics and potential issues

Yes, under certain conditions, you can use structural steel to extend your GEC.

This is often a viable solution when the original GEC is too short. However, it's crucial to do it correctly and meet all code requirements.Here's a detailed explanation: NEC 250.68(C)(1) and (2): Grounding Electrode Conductor Connection to Rod, Pipe, or Plate Electrodes. This is the specific section that permits the use of structural metal as part of the grounding electrode conductor. It essentially allows you to use the building steel as a "jumper" between your shortened GEC and the grounding electrode(s).

Key Requirements and Considerations


Permanently Electrically Connected

The structural steel must be permanently and effectively connected to both: Your original GEC (the stub that's too short) The grounding electrode system (rods, pipes, plates, etc.). This means good electrical contact, typically achieved through welding, exothermic welding (Cadweld), or listed bolted connections (grounding lugs).2.

Continuous Electrical Path

The structural steel you use must provide a continuous electrical path to ground. This means no paint, rust, or other non-conductive coatings that could compromise the connection. Clean the metal to bright before bonding.3.

Adequate Size

The structural steel must be of sufficient size to handle the ground-fault current. While the NEC doesn't provide specific dimensions for structural steel used as a GEC extension, it needs to be robust enough to safely carry fault current. In practice, the steel is usually more than adequate, but you need to ensure the connections are correctly sized.4.

Listed Connectors

Use listed connectors suitable for grounding and bonding. Don't just use any bolt and nut. Grounding lugs specifically designed for connecting to steel are required.5.

Accessibility

Connections must be accessible for inspection and maintenance. You can't bury a connection in concrete or hide it behind drywall without access.6.

Continuity

Verify the electrical continuity of the structural steel section you intend to use. Use an ohmmeter or continuity tester to confirm a low-resistance path between the two points where you plan to make connections.

Practical Steps


Inspect the Steel

Carefully inspect the steel for corrosion, paint, or other issues that could compromise its conductivity. Clean the areas where you'll be making connections to bright, clean metal.2.

Connect to the GEC Stub

Use a listed grounding lug of the appropriate size to connect your GEC stub to the structural steel. Ensure the connection is tight and secure.3.

Connect to the Grounding Electrode System

Use a listed grounding lug to connect the structural steel to the grounding electrode system (ground rods, etc.).4.

Bonding Jumpers (if needed)

If the grounding electrode system includes multiple electrodes (e.g., ground rods), you may need to install bonding jumpers between the electrodes and the structural steel, depending on their physical location.5.

Testing

After completing the connections, use an ohmmeter to verify a low-resistance path between the GEC and the grounding electrode system through the structural steel.

Important Considerations



AHJ Approval

It's always a good idea to discuss this approach with your local Authority Having Jurisdiction (AHJ) before you do the work. They may have specific requirements or preferences.

Documentation

Document the work, including photos of the connections and the type of connectors used. This will be helpful for future inspections.

Alternative: Splice the GEC

While using the structural steel is permitted, the best solution, if practical, might be to splice the GEC with an appropriately sized connector listed for direct burial, ensuring the splice is buried per code. This eliminates any reliance on building steel. However, this requires access to both ends of the wire.

Do Not Use As A Neutral

Under no circumstance can you use the structural steel as a neutral conductor. This is extremely dangerous.

In summary:

You can* use structural steel to extend your GEC under the conditions specified in NEC 250.68(C)(1) and (2). Ensure you use proper connections, verify continuity, and consult with your AHJ. However, a properly made, code-compliant splice of the GEC may be a preferable solution if feasible. Flag for review