Hi all,



I'm doing a project that involves RS422/485 communications over distance of 400m. Is that possible to use LAN cable Cat 5 for such application? If anybody has practical experience with this, pls share your thoughts.



Many thanks.

CAT5 is not shielded. I would definitely use a shielded cable.

Have used it for short runs on prototype cables and it works. I would try it.

I agree with PDL, over that distance you better be shielded..

I would test it without expanding the cable roll in plant because you may need shielded cable. Use twisted pairs between TX and RX and use remaining cables for ground reference.

Even if that works, you might still get problems when the cable is runned through a tray next to VFD motor cables etc...

Twisted pair cable is much more "shielded" than you give it credit. The twists mean that electromagnetic fields hit it with alternating polarities, effectively cancelling out most interference. Twisted pair cable isn't that far off from the capability of coaxial (which produces a true 100% Faraday cage).

If anyone used Cat% instead of screened cable on one of my jobs I would make them replace it with screened cable. Cat5 is useless as a replacement for screened.
This is really important

My general practice would be shielded cable... (0.5mm - 0.75mm) should more then suffice.
Paul is right though
I could not fathom using a solid CATx over a stranded cable though in an industrial application.