A Quick Guide to Choose Flexible Conduit Sizes

flexible plastic conduit

Flexible conduit protect wire and cables in the wire loom of construction or machine industry. They can also be used in household and auto, to make us more easy to move and manage wires. They are a series sizes of flexible conduit. General, flexible conduit vary size from 1/4″ on up, and each conduit sizes have total different outer diameter and inner diameter. Today, we’ll share some quick guide to flexible conduit size. It is easier to choose an available flexible conduit sizes if you know the basic knowledge.

As our experience, there are several factors you need to take into consideration. Be sure to look at all available wires and cables when determining what conduit is best for your application. There are two kinds of flexible conduit, plastic flexible conduit and flexible metal conduit. Be sure to use the correct flexible conduit for job at hand.

Flexible Conduit Fill

The flexible conduit fill is the maximum amount of space that the conductors running through the conduit can occupy. This would be your most important factor in determining the conduit to choose for a job. There are strict regulations in dealing with the fill factor. A cross-sectional area of the conductors inserted would be measured and the code would determine the percent of conduit which could be filled. A conduit can never be filled 100 percent as it is not safe. The code has determined how wires and bundles of wires can safely run through a given flexible conduit.  The table does not address any difference in high or low voltage cables so you can apply the table for both uses. Have this information readily available when shopping for conduits.

The ID and OD

The ID and OD means inner diameter and outer diamter of flexible conduit. OD is the maximum of flexible conduit, and is a fixed number that can not be deviated from. Flexible conduit are always corrugated inner and outer, so we’d better leave more space inner to make wires and cables easier to through. So we should leave 20% space based on inner diameter.

Conduit Rating

It may sound backward but use the diameter of the conduit as a guide to the service needed. It is better to use a conduit that is too big than one that is too small.

We specialize in flexible plastic conduit, flexible metal conduit with fittings. If you have any problems, please feel free to contact us.