How To Trace a Cable

If your cable in question isn’t labeled, here are the Top 5 ways to trace it according to our Facebook group

Simply following the wire in a bundle

Nothing beats manually tracing it to determine where it’s going. This can be extremely time-consuming and the possibility of getting it mixed up with other cables is high, especially if your bundle isn’t combed or has several “divers”

One reader pointed out they use a split-ring, carabiner, or other “loopable” object like a zip tie or velcro to make sure they have the correct cable the whole way.

While manually tracing it, try pulling it back and forth slightly and watch for movement in the bundle ahead of you

ID Number on Cable

One member pointed out you can use that to narrow down the number of cables to ~1000ft from that spool. We suggest checking the jacket color first to narrow it down even further before looking for the serial number and cable length marking

Use your Jedi powers

Many of our community members contributed the ability to locate unlabeled cables to experience. The more you do it, the more intuition you’ll get. Knowing the codes, standards and recommendations also helps. For example, the maximum length of ethernet is 300ft. Knowing that you can quickly narrow down your search radius to a 600′ diameter circle.

Cables also tend to remain on the same floors (this is called Horizontal Cabling) and are distributed between floors with “Trunks”, “Backbones” or “Splines”

BICSI, TIA, and NEC all have important publications to help you learn about the industry.

Tone and probe

This can be a conventional analog tone and probe like the Fluke Pro3000 that’s usually available at your local big box store or if you want to step up your game, upgrade to a digital toner. The Fluke IntelliTone Pro200 has a digital tone and wand that can quickly identify a cable that is connected to a device on the other end. 

Conventional analog toners have a difficult time picking up a signal on the cable if the cable is connected to a device.

Protip #1: You can change the impedance of the tone and help amplify the signal by connecting the black lead to a building ground or if you’re in the ceiling just clip the black lead on the grid. Once you narrow in on your cable you may need to disconnect the building ground to really isolate it. Another reader pointed out you can use the shield in a shielded cable.

Protip #2: When trying to find an individual wire, touching the conductors together will short out the toner and most toners will change their cadence to notify you that’s the correct wire.

Protip #3: While holding the toner in one hand with your finger on the tip and touching the conductor with your other finger on a 66 block, you can quickly isolate a cable. Check out this video on how to do this, but be careful, you may end up with ringing voltage traveling down your arm!

Keep in mind that tone will not pass through a short

Use a TDR

Instead of trusting your Jedi powers, you can estimate exactly how long the cable is with a TDR like the Klein Scout 3

Once you know the length of the cable, subtract a few feet for the vertical components up to the ceiling and down to the rack and you’ll end up with almost the exact distance from where you are to the other end of the cable.

CDP & LLDP

These are protocols that switches use to help network technicians know what device and port they are connected to. Make sure these are enabled on your switches and you can hook up a laptop with Wireshark or try out a device like a LinkSprinter that can read these packets. Some organizations have these turned off for security purposes so check with the network or security team before relying on these or enabling them.

For more tips and tricks like this, follow us on our Low Voltage Nation Facebook Group or check out our YouTube Channel

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