Romex vs Conduit: When to Use Each
NM-B Cable (Romex) vs Conduit (EMT/PVC)
| Feature | NM-B Cable (Romex) | Conduit (EMT/PVC) |
|---|---|---|
| Cost (material) | $0.30-0.80/ft | $1.50-4.00/ft + wire |
| Labor | Fast - one cable | Slower - bend, pull, connectors |
| Residential | Permitted (1-3 family) | Always permitted |
| Commercial | Generally NOT permitted | Required |
| Wet locations | NOT permitted | Permitted (use THWN) |
| Ground path | Requires ground wire | EMT/RMC = ground path |
| Physical protection | Requires nail plates | Inherent protection |
| Expandability | Fixed conductors | Can add/change wires |
| NEC Article | 334 | 344 (RMC), 358 (EMT), 352 (PVC) |
When to use NM-B Cable
NM-B (Romex) is the standard for residential new construction in most of the US. It is fast to install - one cable contains the hot, neutral, and ground all in one jacket. You can run it through wall cavities, attics, and crawl spaces without extra hardware.
For a typical home, Romex cuts wiring labor time by 30-50% compared to conduit. It is permitted in 1- to 3-family dwellings, in dry locations, concealed in walls, floors, and ceilings per NEC Article 334.10. Some jurisdictions (notably Chicago and parts of New York) prohibit NM-B entirely - check your local code before planning a Romex job.
When to use Conduit
Conduit (EMT, PVC, or RMC) is required in commercial buildings, multifamily buildings over 3 stories, wet locations, and any exposed installation where physical damage is a concern. Conduit also gives you future flexibility - you can pull new wires or upgrade circuits without opening walls. EMT is the most common indoor conduit for commercial work.
PVC is the standard for underground and wet locations. RMC (rigid metal conduit) is used where maximum physical protection is needed, such as parking garages or industrial settings.
On the job
Imagine a 30-foot circuit from your panel to a kitchen island outlet. With Romex, you buy a roll of 12/2 NM-B (~$35-45 for 30 ft), drill through studs, and staple the cable in place. Total time: 30-45 minutes for the rough-in.
With conduit, you cut and bend 3/4" EMT (~$12-20 for pipe), add connectors and a box ($8-15 in fittings), then pull individual THHN conductors (~$25-35 for three wires). Total time: 1.5-2 hours. The conduit installation costs roughly 2-3x more but gives you a protected, upgradeable pathway.
Cost comparison
For a typical 2,000 sq ft home with 30 circuits, Romex wiring costs roughly $1,500-3,000 in materials. The same home in conduit (EMT + THHN) runs $4,000-8,000 in materials alone, plus significantly more labor. This is why Romex is nearly universal in residential construction where code permits it.
However, for a single dedicated circuit like an EV charger in an exposed garage, the cost difference is small - $20-40 for Romex vs $40-80 for conduit on a 25-foot run.
InstallationInstallation difficulty
Strip, staple, connect. Basic hand tools.
Bending, pulling, connectors. Requires practice.
Romex is beginner-friendly for permitted homeowner work. It requires a basic tool kit: wire strippers, drill, cable staples, and a non-contact voltage tester. Conduit requires bending skills (EMT bender), threading or gluing (PVC), and knowledge of fill calculations.
Most homeowners can handle Romex for simple circuits; conduit work is typically best left to experienced electricians or motivated DIYers willing to learn proper bending technique.
Related guides
External resourcesTrusted references
Frequently asked questions
Which is better, nm-b cable (romex) or conduit (emt/pvc)?
Neither is universally better - each has specific strengths for different situations. Use Romex for residential where permitted (faster, cheaper). Use conduit where code requires it (commercial, wet, exposed), where physical protection is needed, or where you may need to change wiring later.
Can I use nm-b cable (romex) and conduit (emt/pvc) in the same installation?
Yes, many installations use both where each is best suited. Transition points must be properly connected per NEC requirements. Always ensure the transition is accessible and properly identified.
What does the NEC say about nm-b cable (romex) vs conduit (emt/pvc)?
The NEC specifies where each is permitted and prohibited. Check the specific NEC articles referenced in the comparison table above. Your local jurisdiction may have amendments that further restrict or modify these requirements.
Do I need a permit for this electrical work?
In most jurisdictions, any new circuit or wiring change requires a permit and inspection. Check our state-by-state permit guide for your specific requirements. Working without a permit can void insurance and create liability issues.
Is Romex banned in Chicago?
Yes. The City of Chicago has historically prohibited NM-B (Romex) cable in all construction, requiring conduit wiring throughout. This is a local amendment to the NEC that takes precedence over the national code. If you are working in Chicago, all wiring must be in conduit (typically EMT).
Can a homeowner install Romex themselves?
In many states, homeowners can pull their own permits and do electrical work in their primary residence. However, all work must be inspected and must meet NEC and local code requirements. Check your state permit requirements before starting. Regardless of what is legally permitted, if you are not confident in your abilities, hire a licensed electrician - electrical mistakes cause fires.
NEC 2023 references verified April 2026