NM wiring refers to the use of Non-metallic (NM) sheathed cable, a common type of electrical cable found in residential and certain commercial wiring applications. It's a fundamental component of modern electrical systems in many buildings.
Understanding NM Cable
Non-metallic (NM) sheathed cable consists of two or more insulated electrical conductors (usually copper or aluminum) contained within a flexible, non-metallic outer sheath. This sheath provides protection for the conductors and ground wire, making the cable easier to handle and install in walls, ceilings, and floors.
Common Applications of NM Wiring
NM cables are widely used for distributing power throughout buildings. Based on the provided reference, their primary applications include:
- Residential Wiring: NM cables are frequently employed in homes to wire circuits for lighting and outlets. This makes them a staple for providing power to everyday fixtures and receptacles.
- Commercial Wiring: Non-metallic (NM) sheathed cables can also be used for wiring circuits, such as lighting and outlets in commercial structures. While sometimes restricted in larger commercial buildings, they are suitable for certain applications.
Where NM Wiring is Used
A key characteristic of NM wiring, highlighted in the reference, is its suitability for specific environments. They are:
- Suitable for use in dry areas: This is a crucial limitation. NM cable is designed for indoor locations that are not subject to moisture or physical damage.
- Commonly installed in areas like walls and ceilings. They are pulled through framing members (studs, joists) and terminated at electrical boxes for switches, outlets, and light fixtures.
Typical Locations for NM Cable
- Inside finished walls
- Above ceilings (in accessible spaces)
- Unfinished basements (when properly supported and protected)
- Garages
It is important to note that NM cable is generally not permitted in wet or damp locations, buried directly in the ground, or in locations exposed to potential physical damage without additional protection.
Characteristics of NM Cable
NM cable comes in various sizes and conductor counts depending on the electrical load it will carry and the type of circuit it's intended for (e.g., a circuit for a few lights versus a circuit for a kitchen appliance).
| Feature | Description |
|---|---|
| Cable Type | Non-metallic (NM) sheathed cable |
| Primary Use | Wiring circuits for lighting and outlets |
| Typical Location | Dry indoor areas |
| Environments | Homes, certain commercial structures |
| Construction | Insulated conductors inside a flexible, non-metal sheath |
In summary, NM wiring is the standard method utilizing non-metallic sheathed cable to power lighting and outlets in dry indoor environments, particularly in residential settings and some commercial spaces, as indicated in the reference.
