1. Consult NEC Article 90.2: Scope. This article outlines the types of installations covered by the NEC, including:
- Buildings and structures: Most permanent and temporary installations within buildings and structures, including dwellings, commercial and industrial buildings, and public spaces.
- Mobile homes and recreational vehicles: Installed electrical systems in mobile homes, recreational vehicles, and similar vehicles.
- Floating buildings: Electrical systems on permanently moored floating buildings, such as boathouses and marinas.
- Other installations: Fences, pools, fountains, outdoor lighting, signs, electric vehicle charging systems, and other installations specifically mentioned in the NEC.
2. Check for Exclusions. Article 90.2 also lists installations that are not covered by the NEC, such as:
- Ships: Electrical systems on ships, watercraft, railway rolling stock, aircraft, and automotive vehicles.
- Railways: Electrical systems used exclusively for the operation of railways.
- Underground mine installations: Electrical systems in underground mines.
- Communications systems: Communications systems under the exclusive control of communications utilities.
3. Consider Local Adoption. Even if an installation falls within the NEC’s scope, it’s only mandatory if the local jurisdiction (city, county, state) has adopted it into law. Check with your local building department to verify if the NEC is applicable in your area.
4. Seek Professional Advice. If you’re unsure whether a particular installation is subject to the NEC, it’s best to consult a qualified electrician or electrical inspector for guidance. They can assess the specific installation and advise on applicable codes and regulations.
Here are examples of electrical installations that are typically subject to the NEC:
Covered Installations:
- Houses and apartments: Electrical wiring, outlets, lighting, appliances, and other electrical systems within homes and residential buildings.
- Office buildings: Electrical systems for power, lighting, communications, and data in commercial office spaces.
- Retail stores: Electrical systems for lighting, displays, refrigeration, and security in retail environments.
- Industrial facilities: Electrical systems for power distribution, machinery, lighting, and control systems in industrial plants.
- Schools and hospitals: Electrical systems for power, lighting, safety, and medical equipment in educational and healthcare facilities.
- Public spaces: Electrical systems for lighting, signage, and power in parks, plazas, and other public areas.
- Mobile homes: Electrical systems installed within mobile homes and recreational vehicles.
- Boathouses: Electrical systems on permanently moored floating buildings, such as boathouses and marinas.
- Electric vehicle charging stations: Electrical systems for charging electric vehicles.
Installations Not Covered:
- Car electrical systems: Electrical systems within automobiles are not covered by the NEC, as they fall under automotive industry standards.
- Aircraft electrical systems: Electrical systems on aircraft are governed by aviation regulations, not the NEC.
- Underground mine electrical systems: Electrical systems in underground mines have their own specialized safety codes.
- Utility power lines: Electrical power distribution systems operated by utility companies are typically subject to separate regulations.