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⚡ Code Corner:🔸 NEC 230.6 – Conductors Considered Outside the Building

Sharpen your knowledge with a quick dive into the NEC.

Author

Chris Martinez
July 08, 2025

📘 What NEC 230.6 says:

What it says:
Article 230.6 defines when service conductors are considered to be located outside a building or structure — even if they physically pass through or along it.

This matters for fire separation, clearance, and raceway selection, especially in commercial and multi-meter setups.

Why it matters:
Avoiding "inside-the-building" classification helps:

  • Stay compliant with fire code separation

  • Prevent accidental exposure

  • Avoid unnecessary reroutes

💡 Pro Tip: Don’t assume “underground” means “outside.”
If your service conductors pass under the building slab, they still need 2 inches of concrete cover to be considered outside per NEC 230.6.

📏 A shallow duct bank without that cover could trigger major rework during inspection — or require costly fire-rated construction inside.

✅ Always coordinate your slab edge layout and trench depth with the GC before you pour.

❓ Quick Code Quiz

Choose the correct answer:

Question:
You're running service conductors from a utility transformer to a main switchboard inside a commercial building. Which of the following methods would NOT meet the requirements for considering the conductors “outside” the building under NEC 230.6?

A) Installed in PVC conduit under 3" of concrete
B) Routed through a 1-hour fire-rated wall
C) Encased in 2" of brick inside the building
D) Run in EMT on the outside wall of the structure

Answer below 👇

🧠 Think it through:
230.6 gives four specific conditions. One of these does not meet them.

B) Routed through a 1-hour fire-rated wall

📘 Reference:
Article 230.6 – Conductors Considered Outside the Building

NEC 230.6 requires a 2-hour fire-rated wall, not 1-hour. The other options meet the "outside the building" conditions.