How to Run Ethernet Cable in an Existing Wall

| December 3, 2010

phone system, voip phone system, response point, conferencing systemThere’s always a time when your setting up a VoIP phone system or a Video Surveillance solution, when you find yourself in the need of  adding ethernet cables to your existing network.

With a little planning, some plain old common sense, and a few basic tools, running Ethernet Cable in an existing wall isn’t as difficult as it appears. Always chose an interior walls to run a cable as exterior walls often have solid sheet insulation making it impossible to pass the cable through.

Before starting you will want to gather some basic tools, such as: a flashlight, sheetrock saw/knife, ornamental chain (or nylon string/fishing line with a small fishing weight), drill with a 3/8″ or 1/2″ drill bit. You will also need you jacks and mounting hardware. It is a good idea to identify a path where the Ethernet cable will run from the network or phone equipment to the wall where the jack hardware will be mounted. Make sure the cable path will route over the top of plumbing and pipes, cross electrical wiring at 90 degree angles and never pass the cable over the top of a fluorescent light fixture. The total cable length cannot exceed 328 ft (100 m), including any patch cables. It is generally a good idea to never run the cable more than 300 ft to leave allowance for patch cables.

Visually inspect the wall where the jack hardware will be mounted. Also inspect the opposite side of the wall as well. If the cable is dropping down from the top of the wall, inspect the top, from underneath the floor, inspect below. Make sure there aren’t any obstacles that would prevent the cable from running through the wall to where the jack will be located. For example, gas pipes, water pipes, electrical cabling, or any construction obstacles, such as adjacent walls may be in the way to drill or route the cable. If there is an obstruction, go to plan B if possible – find a new location for mounting the jack hardware.

From the attic, or above a drop ceiling, locate the studs at the top of the wall that are on each side of where the jack hardware will be mounted on the wall. With a pencil or marker, mark a spot between those studs. This will be where the hole is cut, allowing the cable to go into the wall. If the cable is to be routed from underneath, say a crawl space or basement, locate a spot between the studs underneath and mark the location for the hole. Either way, it can be tricky to find the correct spot for this hole and you might need to measure things several ways to find the exact location. My dad always told me “measure twice, cut once”.

For the jack hardware, the hole is usually 16 to 18 inches off the floor and centered between the two studs. Determine the exact distance by measuring from the floor to the center of an existing outlet, which will keep the new jack’s location consistent with the existing construction. The center between studs is typically 7½ inches from one side. I use low voltage rings (purchased from my local Home Depot) for mounting the jack, so centering between the two studs gives more than enough clearance and works best for me.

Now for the fun part, drilling and cutting a hole into a perfectly good interior wall where the jack hardware will be mounted. It is a good idea to double check everything before drilling the holes. If something doesn’t make sense, stop and rethink. I’ve found I can always make the hole bigger if I need to, but not the other way around. It is important to use a drill bit that is a thicker than the diameter than the cable. When ready, drill the hole at the top of the wall.

Next drop a pull string down in the wall through the top hole. A small ornamental chain from the local hardware store is my preference, but nylon string or heavy fishing line can be used. For the string or fishing line, tie on a weight to the end of the pull string, something that will fit through the top hole, like a fishing weight.

Drop the chain or weight through the hole and feed the pull-string through until the end is resting at the bottom of the wall. The chains works well because you can hear it rattling on the inside of the wall all the way down. If there is insulation in the wall you will need something rigid to push the pull string to the bottom. Something like flexible tent poles or a one piece fishing pole, might do the trick. If you are going from the bottom up, you can typically just push the cable through a couple of feet without the need for a pull string.

Confident the pull string is at the bottom of the wall, time to cut a hole in the wall. Use your jack and mounting hardware for dimensions and mark the hole. Use a sheetrock saw to cut the hole. Locate the end of the pull string and attach it to the Ethernet cable. I usually use a link in the chain, or loop the string and tie it in a knot. Remove the four or five inches of the cable insulation, stick the wire through the link or loop, then twist the wire around the cable so it won’t come off when you pull the cable through. Remember however you attach the cable to the pull string it has to go through the hole at the other end.

From the top of the wall, simply pull the pull string through the wall. The end of the Ethernet cable will follow. Once the cable is through the wall and routed to the equipment, cut the cable at the wall end 2 to 3 ft longer than needed. To finish the job, install the jack and mounting hardware, and wire everything up.

Take your time running the first cable and be sure you don’t use excessive force when pulling cable. Scraping cable over a rough or sharp surface will ruin your hard work!

Most find this work rewarding and it will go faster with more hands so get some friends or coworkers to help.

Don’t forget to visit our website www.telcodepot.com to learn more about the tools we have for all your ethernet cabling needs and all our phone system and hosted PBX solutions.

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