Distance Between Supports

[NorthwestPV]

Our company is primarily a high voltage installer. We have been contracted to run all the Data and communication cabling. Our area does not require the cabling to be installed in conduit. The project is built with steel trusses spaced 10' apart. We will need to add support between trusses. The question is, how far apart does cat6 and cat5e need to be supported? I cannot find this in the code book.

 

[hbiss]

Support for LV cables is not something the Code addresses other than it must be installed in a workmanlike manner. That said, 10 feet between supports is too far. If you pulled the cable tight so that the sag was acceptable you could possibly exceed the maximum design tension of the cable and it might not pass certification.

Most steel truss construction that I have seen has black iron stringers at intervals on the bottom chords between trusses. I have always run cables along them. Otherwise you may have to provide your own support. Kindorf channel or even a tensioned steel messenger cable with the data ty-rapped to it (IT guys like velcro).

-Hal

 

[JFletcher]

https://www.bicsi.org/uploadedFiles...entations/Caribbean/TIA-569UpdateOverview.pdf

TIA 569: "Non‐continuous supports located at intervals not to exceed 1.5 m (5 ft)"

As Hal wrote, this is not NEC code, but Telecom/Electronic Industries Association specs. I've always run any indoors type of Catx cable at 5' (or closer) supports. Hilti makes easy slide-in hangers that are wide and support a fair number of cables, but you could use L-clips shot or screwed to the deck with ceiling grid wire, superstrut, all-thread and Sammies, really anything (other than electrical conduit or sprinkler pipes :roll: ) to support the cable between trusses.

Here's a pic of the Hilti clips I've used before:



The top is good for probably 60 cables, the bottom is two clips locked together, each one good for about 20 cables. Keep in mind Cat 6 is fairly heavy and more sensitive to installation to certify; having high point loads on a bundle of cable because it's not supported right could cause a lot of problems.

Those pins are factory and made to be shot with a DX351 powder actuated tool w/clip attachment to concrete decking, but you can remove them and use screws for wood or sheet metal.

 

[hbiss]

I assumed that the trusses supported a corrugated roof deck. If that is correct LV cables should not be attached to the deck for the same reason the Code prohibits it for electrical. Roofers use very long screws.

-Hal