For Conduit:

Sizing for conduit is easy-breezy. Simply bundle the cords that you’ll be inserting into the loom and measure the diameter of the bundle. Then, select a conduit option with an inside diameter that is approximately equal to or greater than the diameter of your bundle.

Conduit tubing is meant to fit quite snugly. That said, if your wire bundle has the exact same measurement as a conduit option, we suggest that you order the next size up.

For Braided Sleeving:

Bundle the cords that you’ll be covering and measure the diameter of the bundle.

If you want a snug fit, choose a braided sleeving option with a slightly smaller diameter than that of your cables. If you want a loose and flexible fit, choose a braided sleeving option with a diameter that is equal to or slightly larger than that of your cables.

Keep in mind that braided sleeving loses 2% to 3% of its length when it expands. Be sure to plan accordingly!

For Heatshrink Tubing:

You have to be a bit careful when measuring for heatshrink because – as you may have guessed – heatshrink shrinks! When it comes to picking the proper size heatshrink, two important terms to remember are nominal diameter and shrink ratio.

Nominal diameter is the original or ‘unshrunk’ diameter of a piece of heatshrink. Shrink ratio is the approximate maximum amount that heatshrink will shrink relative to its nominal diameter. For example, heatshrink with a 1/4” nominal diameter and a 2:1 shrink ratio will shrink to a diameter of approximately 1/8”.

Measure the diameter of the cables you’re covering, including any attached connectors. Then, choose a heatshrink option with a nominal diameter greater than the diameter of your cables AND a shrink ratio that will ensure that the post-shrinkage diameter of the heatshrink is smaller than the diameter of your cables.