Different Types of Flexible Electrical Conduit

Proper cable protection is vital for safe, efficient electrical installations. Flexible conduit offers the durability of traditional conduit while allowing easy routing around corners and obstacles. Below is an in-depth look at the main types of flexible conduit, their construction, and best-fit applications.

1. Flexible Metal Conduit (FMC)

Flexible Metal Conduit, often abbreviated as FMC, is a helically wound steel or aluminum conduit with interlocked ridges that create natural flexibility.

Key Features

• Material: Galvanized steel or aluminum for strong mechanical protection

• Flexibility: Bends without special tools, ideal for tight spaces

• Applications: Commercial buildings, industrial facilities, retrofits, and machinery wiring where vibration or movement is present

FMC is typically used in dry indoor locations, but when paired with appropriate fittings and a plastic coating, it can handle damp environments as well.

2. Liquid-Tight Flexible Metal Conduit (LFMC)

When moisture resistance is critical, Liquid-Tight Flexible Metal Conduit is the go-to solution.

Construction

• Inner core of interlocked galvanized steel

• PVC outer jacket providing liquid-tight protection

Advantages

• Guards against oil, water, and corrosive chemicals

• Suitable for outdoor installations, washdown areas, and HVAC equipment

LFMC meets UL and NEC standards for wet locations and offers excellent durability in challenging environments.

3. Liquid-Tight Flexible Non-Metallic Conduit (LFNC)

For installations where metal conduit is not required, LFNC provides lightweight flexibility.

Characteristics

• Made of PVC or thermoplastic elastomer

• Available in multiple grades: LFNC-A, LFNC-B, and LFNC-C, each with varying wall thickness and flexibility

• Non-conductive and resistant to sunlight, moisture, and certain chemicals

LFNC is widely used for outdoor residential wiring, landscape lighting, spas, and air-conditioning units.

4. Electrical Non-Metallic Tubing (ENT)

Often called “smurf tube” because of its typical blue color, Electrical Non-Metallic Tubing (ENT) is a corrugated plastic conduit that is extremely lightweight.

Benefits

• Quick installation—snaps into plastic fittings without glue

• Permits hand-bending with no heating or tools

• Resistant to moisture and most household chemicals

ENT is ideal for concealed walls, floors, and ceilings in residential or commercial projects.

5. Flexible Metallic Tubing (FMT)

Though similar in appearance to FMC, Flexible Metallic Tubing (FMT) is not a raceway under the NEC and is generally used for fixture whips and motor leads.

Highlights

• Thin-walled spiral metal design

• Excellent for short runs connecting motors, transformers, or lighting fixtures

• Requires protection from physical damage due to lighter construction

6. Flexible Aluminum Conduit

Aluminum flexible conduit offers corrosion resistance and is significantly lighter than steel alternatives.

• Nonmagnetic properties reduce electromagnetic interference (EMI)

• Often used in food processing plants, chemical facilities, and coastal environments where rust is a concern

7. Flexible Steel Conduit with PVC Coating

Combining the strength of galvanized steel with a polyvinyl chloride coating, this conduit withstands exposure to harsh chemicals and continuous moisture.

• Perfect for underground applications and marine environments

• The PVC jacket provides UV resistance and extended service life outdoors

Key Factors When Choosing Flexible Electrical Conduit

Selecting the right conduit requires careful evaluation of the installation site:

• Environmental conditions: Will the conduit encounter water, oil, or corrosive chemicals?

• Mechanical protection needs: Is impact resistance important?

• Temperature range: Verify that the conduit material tolerates the expected operating temperature.

• Electrical requirements: For grounding or shielding, a metallic conduit may be necessary.

Proper fittings and connectors are equally critical to maintain a secure, code-compliant system.

Installation Tips for Flexible Conduit

• Support spacing: Follow NEC guidelines for securing conduit at appropriate intervals.

• Bend radius: Avoid sharp bends that can damage cables or reduce pulling efficiency.

• Sealing: Use liquid-tight fittings when installing LFMC or LFNC in wet areas.

• Grounding: For metallic types, ensure proper grounding to prevent potential faults.

Conclusion

Flexible electrical conduit offers unmatched versatility for both commercial and residential projects. From FMC for indoor dry areas to LFMC for wet industrial environments and LFNC for lightweight outdoor runs, there is a specialized conduit for nearly every application. By understanding the distinct advantages of each type and matching them to your specific needs, you ensure safe, long-lasting, and code-compliant electrical installations.

More details please contact www.ydtcn.com