When it comes to residential and commercial wiring, two common options are BX cable and Romex cable. Both deliver electricity safely, but they have very different construction, applications, and code requirements. If you’re wondering about BX cable vs Romex wiring, this guide will break down the key differences so you can make an informed choice.
bx vs romex wiring
What Is BX Cable?
BX cable (also called armored cable) is an older but still widely used wiring method. It consists of:
Insulated conductors inside
Flexible metal armor on the outside, usually aluminum or steel
In many cases, the armor itself can serve as the grounding path
Typical Uses:
Exposed runs in basements, garages, and industrial/commercial spaces
Areas where wires need mechanical protection
Installations that must comply with local code requirements for armored cable
What Is Romex Cable?
Romex is the brand name for NM (non-metallic) cable, the most common residential wiring today. It consists of:
Insulated conductors (hot, neutral, and ground)
A non-metallic PVC jacket for protection
A separate bare copper ground wire inside
Typical Uses:
Interior residential wiring in walls, ceilings, and floors
Dry, protected spaces where the cable won’t be exposed to physical damage
Common circuits for outlets, lights, and appliances
BX vs Romex: Key Differences
| Feature | BX Cable (Armored) | Romex Cable (NM) |
|---|---|---|
| Sheath Material | Flexible metal armor | Plastic (PVC) outer jacket |
| Grounding | Metal armor can act as ground (older versions may lack a ground wire) | Includes dedicated bare ground wire |
| Durability | High – resists crushing, abrasion, and rodents | Lower – more vulnerable to damage |
| Flexibility | Rigid and harder to cut/strip | Very flexible and easy to work with |
| Installation Speed | Slower, requires special connectors | Faster, simpler, more DIY-friendly |
| Cost | More expensive | More affordable |
| Code Compliance | Often required in exposed areas | Allowed only in dry, protected areas |
BX Wiring vs Romex Wiring: Pros and Cons
BX Cable Advantages:
Tough metal armor protects against damage
Provides built-in grounding in many cases
Meets strict building codes in exposed installations
BX Cable Disadvantages:
Heavier and harder to work with
Requires special tools/connectors
More expensive than Romex
Romex Cable Advantages:
Lightweight, flexible, and easy to install
More affordable for large projects
Ideal for residential interior wiring
Romex Cable Disadvantages:
Not permitted in exposed or damp areas
Outer sheath can be damaged easily
Not as durable as armored cable
Which One Should You Use?
Use BX cable when wiring in exposed areas like basements, garages, and commercial spaces where the cable needs mechanical protection. Many local electrical codes require armored cable in these situations.
Use Romex cable for most residential interior wiring, such as outlets, switches, and lighting circuits in walls and ceilings. It’s faster and cheaper for standard applications.
Conclusion
When comparing BX vs Romex wiring, the choice depends on your application and local code requirements. BX cable provides superior durability and safety in exposed environments, while Romex (NM cable) is the go-to choice for typical residential wiring inside walls.
👉 Always check with your local electrical code before installation, and if you’re not experienced with electrical work, hire a licensed electrician to ensure safety and compliance.
