In short: Wire loom (also called split loom or convoluted tubing) is ribbed plastic tubing that bundles and protects wires from abrasion, heat, and impact. Split loom has a lengthwise slit so wires push in and branches exit easily; solid convoluted loom is a closed tube fed from one end. Size loom by the bundle’s outer diameter — choose a nominal size whose interior comfortably holds the bundle at about 70–80% fill. Standard polyethylene loom handles roughly 200°F; high-temp materials go higher.

What Is Wire Loom?

Wire Loom (Convoluted Tubing): Ribbed (convoluted) plastic tubing used to bundle and protect a group of wires or cables. The ribs give it flexibility and crush resistance. It comes in two forms: split loom, with a lengthwise slit for easy insertion, and solid loom, a closed tube fed from one end.

Wire loom does two jobs at once: it gathers loose wires into a single managed run and shields them from abrasion against edges, heat from nearby components, and physical impact. The main forms:

Split vs Solid Loom: Which to Use

Split loom is the practical default for most wiring. The lengthwise slit lets you push existing wires in without disconnecting anything, and branches exit anywhere along the run — ideal for automotive harnesses, retrofits, and any bundle that splits off. The trade-off is slightly less protection, because the slit can open under heavy abrasion.

Solid convoluted loom has no slit, so wires feed in from one end. It offers the most complete coverage and resists abrasion better, which suits new runs built before the wires are terminated, or harsh environments where the slit of a split loom would be a weak point. If you can build the run from scratch and want maximum protection, use solid; if you’re working with terminated wires or need branches, use split.

How to Size Wire Loom

Loom is sold by nominal size, but the number to match is your bundle’s outer diameter, not the wire count. Bundle the wires, measure the bundle’s overall diameter, and pick a loom whose interior holds it at about 70–80% fill — snug enough to stay put, loose enough to flex.

Overfilling makes the loom rigid and hard to route and can force the split open; underfilling lets the bundle rattle. Aim for the middle.

Material and Temperature

Match the loom material to the heat it will see. Standard polyethylene is the common, economical choice; polypropylene and specialty high-temp grades extend the range for engine-bay and industrial heat.

For wiring near exhausts or other high-heat sources, pair high-temp loom with heat-reflective sleeving rather than relying on standard polyethylene alone.

Installing Split Loom

Lay the bundled wires along the slit, then open the loom by twisting it slightly and press the wires through the slit a section at a time. Let branches exit through the slit wherever they break away. Secure the loom at intervals with cable ties — spacing them every 6–12 inches keeps the loom from sliding and the slit from gaping. Leave a little slack at bends so the convoluted tubing can flex without kinking, and avoid stretching the loom tight, which opens the slit and reduces protection.

Conclusion

Wire loom protects and bundles in one step — pick split loom for access and branches, solid for maximum protection, size it by bundle diameter at 70–80% fill, and match the material to the heat it will see. Secure it every 6–12 inches with cable ties and leave slack at the bends.

Shop split loom, convoluted tubing, and braided sleeving at cabletiesupply.com/collections/wire-loom. Free shipping over $99, free returns. Questions on sizing? Call 866-455-8437.