Let's break down the requirements and applicability of 250.104(C) in your situation.

Understanding 250.104(C) (Bonding of Exposed Structural Metal)

Section 250.104(C) of the National Electrical Code (NEC) covers the bonding requirements for exposed structural metal that is interconnected to form a building frame and is not intentionally used as an equipment grounding conductor. It essentially mandates bonding of such metal to the electrical grounding system to minimize potential differences and provide a path for fault current back to the source.

Key Considerations for Your Situation



"Exposed Structural Metal"

This is the critical phrase. Generally, "exposed" means accessible without damaging the building finish. The definition of "exposed" in the NEC is "capable of being inadvertently touched or approached nearer than a safe distance by a person." In your case, because the steel beams will be covered in drywall, they are not considered "exposed."

Not Likely to Become Energized

This is also a valid point. Since the steel beams are not part of the electrical system and not in contact with electrical equipment (and assuming they are installed correctly to prevent such contact), the likelihood of them becoming energized is low.

Does 250.104(C) Apply? Likely Not. Given that the steel beams will be covered in drywall, they are not considered exposed structural metal according to the NEC's definition. Therefore, 250.104(C) doesn't automatically apply.However, Consider This



Local Amendments

Local jurisdictions (cities, counties) can and do amend the NEC. It's imperative to check with your local electrical inspector or authority having jurisdiction (AHJ) to confirm whether they have any specific requirements for bonding structural steel, even if it's concealed. Some jurisdictions may have stricter interpretations or rules than the national code.

Other Relevant Sections

Even if 250.104(C) does not apply, there may be other sections in Article 250 that are relevant, particularly related to grounding and bonding of metal enclosures and raceways.

Prudence and Safety

While not explicitly required by the NEC in your specific scenario, it may still be prudent to bond the steel beams. Bonding can enhance safety by minimizing potential differences and providing an additional grounding path. This is especially relevant if the ceiling cove area will contain electrical equipment or raceways in the future.

Recommended Steps


Consult with the AHJ

The most important step is to discuss your project with your local electrical inspector or the AHJ. Explain the situation (steel beams covered in drywall, not exposed) and ask for their interpretation of the NEC and any local amendments.2.

Review the Project Specifications

Carefully review all project specifications and drawings. There might be specific bonding requirements outlined in the project documents.3.

Consider Bonding for Extra Safety

Even if not required, consider the benefits of bonding the beams for enhanced safety, especially if the area will contain electrical equipment in the future. Document your reasoning.4.

Provide a rationale to the AHJ why 250.104(C) should not apply. Reference the NEC definition of exposed and how it does not apply to this situation.

In Summary:

While NEC 250.104(C) likely doesn't apply directly to your situation due to the concealment of the steel beams, verification with the local AHJ is crucial. They have the final say and can clarify any specific requirements or interpretations. It's also wise to consider the potential benefits of bonding for added safety, even if not mandated. Flag for review