What Is Romex?
Romex is a common trade name for nonmetallic-sheathed electrical cable used in building wiring. The cable contains insulated conductors and a grounding conductor inside a protective outer jacket. Electricians route it through approved spaces to supply outlets, switches, lighting, and other electrical devices in many residential construction projects.
Quick Facts About Romex
Category
Nonmetallic-sheathed cable
Used for
Residential branch-circuit wiring
Common confusion
Romex is a brand name for a type of NM cable
Also called
NM-B Cable, Nonmetallic Cable
Often discussed with
New Construction Electrical Installation
Key Takeaways About Romex
- Its outer jacket groups the conductors into one cable.
- Installation depends on the space, wiring method, and local requirements.
- Romex is a brand name, while NM cable is the broader term.
How Romex Works
Romex carries electrical current through insulated conductors contained within a shared jacket. A separate grounding conductor supports the circuit's grounding path. The jacket keeps the cable assembly organized as electricians route it through wall cavities, ceilings, and other suitable building spaces.
Related glossary terms: Conduit, Electrical Grounding, Junction Box.
During new construction, electricians select cable that matches the circuit design and connect each conductor to the correct device or termination point. The cable markings identify its construction and conductor characteristics. Conduit may be used when the wiring path or conditions call for a different wiring method. A junction box protects and contains permitted connections where cable sections meet.
From the GMB Electric team
When we install Romex on new construction projects, we plan the cable path before walls close and keep each run organized. We check the jacket, conductor identification, box connections, and route against the project design before the wiring is covered.
Romex in Practice: A Real-World Example
For a new home, Romex may run from the electrical panel through wall cavities to supply bedroom receptacles and lighting switches. The electrician secures and terminates each cable as the construction layout requires.
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Related Terms
Conduit
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Electrical Grounding
Electrical Grounding is the intentional connection of electrical equipment and systems to the earth through a…
Junction Box
Junction Box is an enclosed electrical box that protects and contains connections where wires join, split…
Neutral Wire
A neutral wire is a circuit conductor that carries current back to the electrical panel from…
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Have Questions About Romex?
Contact GMB Electric for practical guidance on Romex and related 24 hour electrician work in Indianapolis.