It is used for nearly all residential electrical devices such asGFCI outlets,lights, and walloutlets.
Learn the similarities between NM wire and Romex wire.
What Is Non-Metallic (NM) Electrical Cable?
The Spruce / Kevin Norris
Here’s a more in-depth look.
Older NM cable may use a white outer jacket, regardless of the wire gauge of the individual conductors.
Tomake connectionswith devices, cablesheathing is ripped laterallywith a metal rig called a cable ripper.
The Spruce / Kevin Norris
Wire Insulation
The sheathing’s individual wires (conductors) areinsulated with color-codedPVC (polyvinyl chloride).
The individual conductors normally have black, white, and red insulation.
This paper can be snipped and discarded in the ripped portion of the cable.
The Spruce / Kevin Norris
Wires (Conductors)
Each electrical wire within the sheathing is made of soft, uncoated copper.
For example, choose the hole labeled “12” tostrip the insulationfrom 12-gauge wire.
Other brands have also begun to incorporate a similar coating.
As required by electrical codes, the wire gauges and the metallic content will be the same.
Rome Cable Corp. was also a major source of aluminum wire produced by its parent company Alcoa.
Aluminum wire is inferior to copper wire and its presence is considered to be dangerous in the home.
With all factors considered, do-it-yourselfelectricianswill find their projects easier and cheaper to complete when using NM wiring.
Lighter than metallic sheathed wiring, NM wire is easier to unspool and straighten out.
NM wire pulls easily through holes in studs because of the smooth sheathing.
In the case of Romex, a coating is added that makes the sheathing more slippery.
NM cable is simple to cut with just a set ofside-cutting pliers.
it’s possible for you to cut the sheathing with a utility knife and rip it back by hand.
NM cable is easier toattach to framing members, requiring only lightweight plastic cable staples.
In these instances, the electrical code calls for conduit installations.
NM cable also needs to have some sort of protection in certain applications or when not inside a wall.
NM cable also cannot be used above drop ceilings in light commercial applications.
Running Romex in conduit is not standard practice, but many jurisdictions allow it.
Generally, you’ll want topull individual THHN or THWN-2 wiresthrough conduit, not Romex or NM wire.
you could generally run two Romex wires through a single opening in a stud.
Larger openings allow more Romex wires.
Article 334 Nonmetallic-Sheathed Cable: Types NM, NMC, and NMS.
National Electrical Code (NEC).
