Let's break down the requirements for wiring an electric thermostat located in an interior wall with no insulation.

NEC (National Electrical Code) Considerations Protection from Physical Damage

The primary concern of the NEC is protecting conductors from physical damage.

Type of Wiring Method

The NEC permits various wiring methods, including NM cable (Romex), conduit (EMT, PVC, etc.), or other approved methods.

Regarding Conduit (Specifically)



NEC generally doesn't require conduit for wiring in interior walls, especially if the wiring is NM cable (Romex) and is adequately protected from physical damage. An interior wall with drywall or similar facing typically provides adequate protection.Why Conduit Might Be Used (Even If Not Required)



Future Modifications

Conduit allows for easier future wiring changes or additions. You can pull new wires without disturbing the wall finish.

Local Code Requirements

Some local jurisdictions (cities, counties) do have stricter codes than the NEC. They might require conduit in certain situations, even for residential interior walls. Always check with your local building department.

Increased Protection

While drywall typically provides enough protection, you may want more protection in areas where there might be more foot traffic.

Conduit may be required if your state's electrical code follows older NEC requirements.Alternatives to Conduit



NM Cable (Romex)

This is a very common wiring method for residential interior walls. Secure the NM cable to studs or framing members per NEC requirements.

Other Approved Wiring Methods

The NEC has a list of wiring methods permitted for specific applications.

Here's what you should do


Check Local Codes

This is the most important step. Contact your local building department or electrical inspector. Ask if there are any local amendments to the NEC that require conduit for thermostat wiring in interior walls.2.

Consider Future Needs

Even if conduit isn't required, think about whether you might want to make changes later. Installing conduit now can save you time and effort in the future.3.

Adhere to NEC Requirements

Regardless of whether you use conduit, make sure your wiring installation complies with all applicable NEC requirements, including proper wire sizing, overcurrent protection, grounding, and securing of cables.4.

Permitting

Depending on the complexity, your local permitting and inspection office may require a permit to do the work.

Disclaimer: I am an AI chatbot and cannot provide legally binding advice. Always consult with a qualified electrician and your local building department before performing any electrical work. Electrical work can be dangerous if not done correctly. Flag for review