Okay, let's break this down and find you the code references you need. The inspector's reasoning sounds incorrect based on typical residential wiring practices, but we need to be precise.

Here's the situation as I understand it

You installed an Enphase solar system on the roof. You ran 12/2 Romex (NM-B cable) in the attic to carry the 240V AC from the solar components (likely a combiner box or similar) to the electrical panel. The inspector is requiring conduit for this Romex run, citing the 240V voltage as the reason. You have other 240V circuits in the attic using Romex without conduit.

Why the Inspector is Likely Wrong (and the Code to Support You)

The voltage alone is almost certainly not a valid reason to require conduit for Romex in a residential attic. Romex (NM-B) is commonly used for 120V and 240V circuits in residential buildings. The key considerations are physical protection and how the attic is used.

Here are the relevant NEC sections to cite


NEC 334.10 Uses Permitted

This is the main section that defines where NM cable (Romex) can be used. It generally permits NM cable for both exposed and concealed work in normally dry locations.

Important

Make sure the attic is a dry location. If it's subject to dampness or moisture, NM cable might not be appropriate.2.

NEC 334.12 Uses Not Permitted

This section lists where NM cable is not allowed. The most relevant sub-sections here are:

(A)(1) In any dwelling or structure not specifically designed for human habitation... This isn't relevant to your situation. (A)(2) Exposed in damp or wet locations... You've stated it's a dry attic, so this isn't the issue. (A)(11) Where subject to physical damage. THIS IS THE MOST IMPORTANT SECTION TO CONSIDER. The inspector might be arguing that the attic environment makes the Romex susceptible to physical damage. This is where you need to counter with how the Romex is installed.3. NEC 320.23 In Accessible Attics

This section is very important! It gives specific rules for running AC cable (another type of cable that looks similar to NM/Romex) and NM (Romex) cable in attics. "Where run across the top of floor joists, or within 7 feet of the floor or floor joists across the face of rafters or studding, in attics and roof spaces that are accessible, the cable shall be protected by substantial guard strips that are at least as high as the cable." "Where such spaces are not accessible by permanent stairs or ladders, protection shall only be required within 6 feet of the nearest edge of the scuttle hole or attic entrance."

How to Respond to the Inspector (and what to document)


Be polite and professional. Start by asking the inspector to clarify exactly which code section he believes is being violated. Don't be confrontational. A simple, "Could you please provide the specific NEC section that requires conduit in this situation? I want to make sure I understand the requirement." can be helpful.2. Document the Installation



Take pictures. Lots of them. Show how the Romex is run. Show that the attic is dry. If you can demonstrate the attic is dry you can show the inspector the uses permitted. Document the accessibility of the attic

Determine if the attic has permanent access (stairs/ladder). Document the distance the wire is from the access point.3.

Reference the Code (Calmly and Clearly)

"With all due respect, I believe the installation meets the requirements of NEC 334.10, which permits the use of NM-B cable in dry locations for both exposed and concealed work." "The cable is not subject to physical damage, as it is run [describe how it's run - e.g., along the top of the joists, secured properly with staples, not dangling, etc.]." "If the inspector is concerned about physical damage within 7 feet, it is guarded by the substantial guard strips shown in the pictures."4.

Escalation (If Necessary)

If the inspector is still insistent, ask to speak with their supervisor or the head of the inspection department. Be prepared to calmly explain your understanding of the code and why you believe the installation is compliant.

Important Considerations



Physical Damage

The biggest sticking point will be whether the Romex is subject to physical damage. If the attic is used for storage, or if there's a high likelihood of someone walking or placing items on the cable, the inspector might have a point. If the cable is neatly run along joists or rafters and protected from accidental damage, you have a strong argument.

Local Amendments

Be aware that some jurisdictions have local amendments to the NEC. It's possible (though less likely) that there's a local rule requiring conduit in attics, regardless of voltage. Ask the inspector for a copy of this amendment.

Manufacturer's Instructions

Check the instructions for the Enphase system. While unlikely, it's possible Enphase requires conduit in certain situations.

Example Scenario & Response

Let's say the Romex is run across the top of the joists, within 5 feet of the attic access (a scuttle hole), and without any guard strips.In this case, the inspector would* be correct. You would need to add guard strips according to NEC 320.23.Your response might be:"Okay, I understand your concern. According to NEC 320.23, because the cable is run within 7 feet of the attic access and across the top of the joists, it needs physical protection. I will install guard strips along the run to comply with that requirement. I'll schedule a re-inspection once that's complete."

Disclaimer: I am an AI chatbot and cannot provide legal or electrical code advice. This information is for educational purposes only. Always consult with a licensed electrician or qualified electrical inspector for specific code interpretations and compliance.Good luck getting this resolved! Remember to be polite, professional, and prepared with the code references. I hope you can get this resolved quickly! Flag for review