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When selecting liquidtight conduit for an application, it is important to remember the different advantages that each type of conduit offers. In the nonmetallic liquidtight offering, there are several choices you can select depending upon your application.
There are four options available: Type B PVC Conduit, Type B PVC Tubing, Type A Conduit and Nylon Liquidtight Tubing.
Type B PVC Conduit
Also known as FNMC-B, or LFNC-B, this is the most popularly used conduit. Typically helically wound, it contains a spiral of rigid PVC reinforcement imbedded within a PVC wall. Its uses include air conditioning hookups, machine tools, cable carriers, outdoor wiring, automation equipment manufacturing and direct burial applications. When selecting FNMC-B conduit, there are three questions you should ask yourself:
- Is temperature important? There are two variations of conduit temperature ratings available. They are the 80 degree Celsius-rated product, and 105 degree Celsius-rated product. If you are in an area that will exhibit high temperatures, you want to make sure your product is properly rated.
- Will the conduit be exposed to outdoor light? If your product is exposed to the outdoors, ultraviolet (UV) resistance will be an important factor in selecting your conduit. You will want to make sure that you are selecting a product with a UV-resistant rating. This conduit often is easily identified by its black color.
- Will it be exposed to water? If you are in an environment that will be exposed to excessive water, possibly in areas where temporary submersion can occur, you want to make sure you select a NEMA 6P (submersion-rated) system.
Type B PVC Tubing
Not to be confused with conduit, this extra flexible liquidtight nonmetallic tubing is lightweight and cuts easily. The thin, flexible PVC skin allows for greater movement for many original equipment manufacturer (OEM) applications. It is used for wiring harnesses, machine tool builders and robotic applications. It is co-extruded from both flexible and rigid PVC. Because it is considered tubing, and not a conduit, it is limited in its applications outside of OEMs.
Type B Conduit & Tubing Fittings
Generally, the fittings used for the conduit are the same as the conduit itself. Selecting the correct fitting is as important as selecting the correct conduit. Metallic fittings, for example, are ideal for strength in abusive environments, but do not perform as well as Nylon in extreme corrosive environments.
Non-metallic conduit fittings are available in both PVC and nylon. The nylon fittings are stronger than the PVC fittings, and are recommended for environments in which conduit may be subjected to abuse, such as people standing on it to reach highly placed objects.
