What are the Differences Between Liquid-Tight Flexible Non-Metallic Conduits?
When it comes to protecting electrical wiring in demanding environments, liquid-tight flexible non-metallic conduits (LFNC) are one of the most reliable solutions. These conduits are manufactured from durable PVC conduit material, giving them excellent resistance to moisture, oils, chemicals, and sunlight exposure.
At Anamet Electrical, we offer two primary types within this category: LFNC-A conduit and LFNC-B conduit. Both are recognized by the National Electrical Code (NEC) and fall under the broader family of non-metallic conduits, but their construction and fittings differ in ways that impact performance and installation.
In this article, we’ll break down the differences between LFNC-A and LFNC-B conduits, helping you understand which option is best suited for your project. Whether you’re working indoors, outdoors, or in underground applications, choosing the right type of liquid-tight conduit is key to safety, durability, and code compliance.
LFNC-A (Type A Conduit)
LFNC-A conduit is engineered for maximum flexibility and durability, making it an excellent choice for both commercial and industrial environments. Its reinforced design not only allows easy routing
through tight spaces but also delivers robust protection against bumps, abrasion, and impact. This extra toughness makes LFNC-A conduit especially valuable in high-traffic areas where conduits are more likely to be disturbed or exposed to wear.
Construction and Design
To achieve this performance, LFNC-A conduit is constructed with a smooth PVC inner core bonded to an oil-resistant PVC outer cover and further strengthened by a nylon fiber braid between the two layers. The NEC defines LFNC-A conduit as having a smooth, seamless inner core with reinforcement layers. This layered design provides superior mechanical protection compared to other non-metallic conduit options.
Why Choose LFNC-A?
Because of its robust structure, LFNC-A conduit offers multiple long-term benefits:
- High abrasion resistance ensures it withstands contact in high-traffic or exposed installations, reducing the likelihood of damage.
- Impact resistance helps protect wiring even in environments where equipment, carts, or tools may bump against conduit runs.
- Lower replacement costs thanks to its extended service life and reduced need for maintenance.
- Flexibility and light weight still make it easy to install in complex layouts.
- Chemical, oil, and moisture resistance allow it to perform reliably indoors and outdoors.
Fittings
When installing LFNC-A conduit, it’s essential to use the proper fittings. Type A fittings are designed specifically for this conduit, with a bell flange that secures the conduit jacket and a plastic ferrule that threads tightly into the conduit core. Using the wrong fitting compromises the seal — only Type A fittings provide a true liquid-tight connection
LFNC-B (Type B Conduit)
LFNC-B conduit is designed with a stronger wall structure for enhanced durability. Its reinforcing coil makes it ideal for installations that require added protection, such as direct burial or concrete encasement. While it maintains flexibility along its length, it resists deformation, making it especially well-suited for more demanding environments.
This strength comes from its construction: LFNC-B conduit features smooth PVC inner and outer walls with a co-extruded PVC reinforcing coil embedded in the wall itself. The NEC defines LFNC-B conduit as having a smooth inner surface with integral reinforcement
Thanks to this design, LFNC-B conduit provides excellent long-term durability. The embedded coil strengthens the wall while allowing the conduit to remain flexible. It resists oils, chemicals, and harsh outdoor conditions, and it is rated for use in wet locations, direct burial, and concrete encasement depending on the size of the conduit.
Just as with Type A, proper fittings are critical. Type B fittings include a center tube that inserts into the core of the conduit, with concentric flanges compressed by a gland nut to lock against the outer wall. This ensures a tight and secure seal. Using Type A fittings on LFNC-B is not permitted — only Type B fittings can create a proper liquid-tight connection.
Choosing Between Type A and Type B
Both LFNC-A and LFNC-B conduits are manufactured from high-quality PVC and provide reliable protection for electrical wiring. However, the differences in construction make one option generally more versatile and longer lasting.
- Choose Type A (LFNC-A) if you want the most robust and dependable solution. Its reinforced design provides superior resistance to bumps, abrasion, and impact, making it ideal for high-traffic or exposed areas. In addition to excellent flexibility and ease of installation, LFNC-A reduces the risk of damage and replacement costs over time — delivering stronger long-term value.
- Choose Type B (LFNC-B) when you need a durable conduit for underground runs or concrete encasement, but don’t require the same level of abrasion resistance. While it provides reliable performance, its coil reinforcement is better suited for static protection rather than high-contact environments.
In most cases, LFNC-A conduit offers greater durability and lifecycle savings, making it the preferred choice for demanding applications where conduit integrity is critical.
Which Conduit is Right for You?
Understanding the differences between LFNC-A and LFNC-B conduits makes it easier to choose the right product for your project. Both offer the protection and reliability of liquid-tight non-metallic conduits made from PVC, but each is engineered with unique reinforcement and requires its matching fittings for a proper seal.
At Anamet Electrical, we offer more than just LFNC-A and LFNC-B — our selection includes a wide range of liquid-tight conduit options, covering both metallic and non-metallic conduit solutions. Whatever your application, we can help you identify the conduit system that delivers the best protection, performance, and compliance.
Explore our complete line of liquid-tight conduit solutions today and find the right fit for your application.