What Is A Flexible Electrical Conduit?
A flexible electrical conduit is a tube that provides protection to wire and cable while still allowing some degree of flexibility.
The protection it offers is mostly mechanical, though some types of conduit can also protect from water, corrosion, and other types of environmental impact. Sometimes, a cable tray may be used as an alternative to a cable conduit. Flexible electrical conduit is made of plastic, fiber, or metal. Common metals are aluminum and steel, while common plastic is PVC.
Keep reading to learn more about different types of flexible conduit, their applications, and the way they differ from rigid electrical conduits.
Types Of Flexible Conduits
- A flexible metal conduit (FMC) is a standard type of flexible conduit. Its main characteristic is its flexibility. The conduit can be used in sealed and exposed conditions. This type of flex raceway is not recommended for the outdoors and wet conditions. This type of conduit is extensively described in Article 348 of NEC. It is suitable for dry locations.
- Liquidtight flexible metal conduit (LFMC) is a watertight outdoor electrical conduit because of its plastic sealed coverage that protects from water. The cable can be used for outdoor applications and direct burial.
- Non-metallic flexible conduit consists of PVC. It is inexpensive and suitable for outdoor applications such as the backyard. Flexible electrical pvc conduit is equally fine to be placed indoors in walls and ceilings. Non-metallic conduit can be liquid-tight. In this case, it is called LFNC and is suitable for direct burial.
Applications of Flexible Conduit
- Building construction: flexible conduit is used during the construction of commercial and industrial buildings. The use in residential buildings is also a possibility, albeit a rarer one.
- Runs of wires indoors, such as between the wall box and an appliance.
- Outdoor equipment: spa, pools, garden equipment, etc. The conduit has to be liquid-tight for such applications.
Flexible electrical conduit can be used to connect junction boxes to electric appliances, route critical circuits, and connect lighting fixtures.
Flexible Conduit vs. Rigid Conduit
Two most popular types of cable conduit are flexible and rigid conduit.
A rigid conduit is a solid metallic conduit that offers no flexibility, but gives good protection. Flexible conduit, on the other hand, can be bent and twisted as many times as required for an application.
Rigid conduit has several subtypes:
- EMT, or electrical metallic tubing, is the lightest of them all.
- IMC, or intermediate conduit, has a thick galvanized wall for outside applications
- GRC, or Galvanized rigid conduit, is the thickest conduit for most demanding industrial conditions.
Rigid conduits are mainly used in industrial applications and for straightforward cable runs that do not require much twisting and turning, like from the house to the basement. Compared to flexible electric conduits, they are not as easy to modify. However, rigid conduits are more durable, which makes them suitable for harsher industrial conditions.
Types Of Flexible Conduit On The Market
Here are some of the common types of flexible conduit available at NNC:
- Reduced Wall Flexible Steel Conduit Galvanized - this interlocked conduit is made of high-grade hot dipped zinc galvanized low carbon steel. There is also a version of this conduit without the reduced wall.
- Ultraflex Liquid Tight Flexible Conduit is a liquid-tight non-metallic conduit for non-conductive raceways. It is made of flame-resistant PVC and is for the non-UL liquid-tight raceway.
- FlexCon Extra-Flexible Steel Conduit - as the name suggests, this ultra-flexible conduit is made of steel.
- UL Type LFNC-B Liquid Tight Flexible Non-Metallic Conduit PVC Jacket - a rugged non-metallic PVC conduit with a rigid PVC spiral core for strength. Created for non-conductive raceways and suitable for direct burial.
- Extra Flexible Steel Conduit Non-UL Galvanized - flexible steel conduit for non-UL applications.
