Cable Tensioning, How much should I tighten my cables?

Chris Baker

One extremely common question is: How much should I tighten my cables?

The short answer is: Tight enough to pass code, which in most areas is tight enough to ensure a 4-inch sphere does not push through the lines easily.

The Key to cable railing is cable spacing and the spacing between support posts.

If you space your posts 4 feet apart and the cables 3 inches apart you will pass any code that we have ever heard of or have come in contact with. The further your support posts are from each other the easier it becomes for your cables to be separated. For the 4″ sphere rule your lines should only be able to move 1/2″ up or down.

4 inch spacing no good 3inch cable spacing good

"But what if I don't want a bulky post every 4 feet? PanoRAIL can send you a simple and sleek 1/4″ thick flat post as a cable support and you are set! Space your structural posts every 8 feet and using flat intermediate posts in between your rail will be even more of a space opener and view enhancer!

Tightening or Tensioning Cable railing systems is like tuning a guitar at first in the sense that you will need to tune the lines once or perhaps two more times after the initial setup. The system under tension will settle over the first week or two and will need to be adjusted but should only be slight.

For wood posts you will see some loosening as the weather transitions from winter to summer. There is a natural expansion/contraction cycle that happens to wood through the year as humidity rises and falls. This is most notable with pressure treated pine. Redwood and cedar are more stable and don't see as much moisture infiltration. 

Be careful:

As you tighten each line you may discover that the previously tightened cables are now loose again. If you overtighten a line just back it off slightly as overtightening effectively loosens the other lines. These wires and tensioning devices (turnbuckles) are strong 🙂 Tighten by feel and try to tighten up to, and not beyond the previous wire.

Cable Railing is a fun process and will last the test of time with minimal cleaning and maintenance. We hope this information on how to tighten cable railing has been helpful. Feel free to call and one of our pros will guide you along your way.