Tips or tricks for replacing ethernet cables in walls?
August 24, 2014 4:00 PM   Subscribe

I have a bunch of ethernet cables running through my walls. I imagine they're at best Cat 5. I'd like to replace them. I have a half-assed plan for doing so. Will my half-assed plan be at all likely to succeed? Any way to increase my chances?

I have four cables all starting from a room on the first floor of my home (which I'll call "the central room"), and running through the walls to four other rooms - one to a nearby room on the first floor, and the others to various rooms on the second floor (including some that are pretty far away even in an overhead view sense). I have no idea where the cables run internally, or if perhaps there are internal junctions along the route that they plug into, or even perhaps if they're stapled to studs or something.

My half-assed plan is to assume that they're not stapled or plugged into junctions or whatever, and:

(1) Remove the wall cover that they all plug into in the central room.

(2) Unplug them from the... ethernet equivalent to an outlet box that I assume I'll find behind it.

(3) For each one, duct tape an end of the new (replacement) cable to the end of the existing (in-wall) cable.

(4) Tie a very long piece of string to the second end of the replacement cable, just in case I underestimate the length of cable needed.

(5) For each one, go to the other room, remove the wall cover, and start pulling on the old cable till I get the new cable to the other room.

(6) De-duct tape, plug in new cable, replace wall cover, etc.

I am concerned about the possibility of it snagging on something. I am also concerned about the possibility that I shouldn't "assume that they're not stapled or plugged into junctions or whatever". I am furthermore concerned by the fact that I have no idea what I'm doing.

Any tips? Thanks.
posted by Flunkie to Home & Garden (19 answers total) 5 users marked this as a favorite
I wouldn't bother with this at all.

Sure, we're up to Cat 6 now, but there's also wireless and frankly that's the technology that's going to prevail going forward.

You are pretty much replacing an obsolete technology with a soon to be obsolete technology.

But, if you feel you must, here's an article that you may find helpful.

I will say that most wiring of this sort (telco too) is run through the attic. You may want to take a peek up there and see if the hub is up there, if so it's a bit easier than all that fishing you're planning on doing. FWIW, Fish Tape is exactly what you need, not duct tape.

If I were you, unless I had a COMPELLING reason for doing this, I'd buy a really good wireless router and go about my life. It may be cheaper than rewiring.
posted by Ruthless Bunny at 4:17 PM on August 24, 2014 [1 favorite]

That is exactly how we did it. It worked for most of them but one cable snagged or was attached somewhere and wasn't possible. Still we managed to rewire three out of four cables.
posted by lollusc at 4:22 PM on August 24, 2014

If I were you, unless I had a COMPELLING reason for doing this, I'd buy a really good wireless router and go about my life. It may be cheaper than rewiring.

I could not live like this. I wired my house for Ethernet when we moved in 3 years ago, and I am very, very happy with the decision. It was a couple weekends of pain in my ass but it's over now. I have a central server that stores all sorts of media and am frequently copying huge files all over the place and the speed and reliability are hugely convenient.

Your plan will work, unless it doesn't. I mean, like you say, "assuming they're not stapled or plugged into junctions or whatever." When I did this, I got a stapler and I stapled the cables in the attic along the wood beams at junctions and in general every 6 - 8 feet.... So, if I were to try this, it would likely not work... but, I will say, at several points in the process, after I completed a particularly irritating run I would use the technique you described to pull several more lines over, and it usually worked well. Sometimes it would get caught up in insulation, or around a joint, but more or less it worked out.

Worst case, you have to go to Home Depot and get a wire fish pole and watch some YouTube videos on technique and practice some patience and drill a couple holes... I ran a cable from the basement up to the 2nd floor through the central access conduit of our home, and it left me deeply scarred, but I fucking did it.
posted by kbanas at 4:23 PM on August 24, 2014 [2 favorites]

Oh actually I misunderstood you. We did this duct taping and pulling up into the ceiling, which is where they all ran to. And then back down to each outlet. But we did it the way you suggest.
posted by lollusc at 4:25 PM on August 24, 2014

(3) For each one, duct tape an end of the new (replacement) cable to the end of the existing (in-wall) cable.

Don't do this, by the way. I would go online and buy a spool of un-terminated Ethernet (500 feet or so)... however much you need. It's really inexpensive. Then tape and pull. You can make sure the runs are the right length, and then you can simply cut the cable and terminate the ends. You need a crimping tool and a little practice, but it's really not that hard.

The added advantage is that unterminated cable is much, much easier to pull through the walls, as the RJ-45 connector can snag on stuff.
posted by kbanas at 4:28 PM on August 24, 2014 [14 favorites]

Feel free to send me a mail through the site if you have additional questions. I do not profess to be a guru, but I did it and when I started I was intimidated and not sure at all that I knew what I was doing, so we probably will have similar questions. Maybe I can be of assistance.
posted by kbanas at 4:30 PM on August 24, 2014

CAT5e will work great with gigabit Ethernet. CAT5 will often work. You yourself don't even know what's behind those walls. Are you having a problem? Do you need more than gigabit speeds? Or do you just want to replace the wiring because it's a decade or two old? Or... ?

I would strongly recommend testing before ripping out cable if this is just based on conjecture. I strongly suspect that you'll find out that the wiring is just fine.
posted by eschatfische at 4:41 PM on August 24, 2014 [1 favorite]

Thanks for the replies so far. To clarify on a couple of fronts: I'm aware of the existence of wireless. Yes, I am having throughput issues. Correct, I do not know exactly what's in there, but I do know that Cat 6 did not exist when it was installed, and Cat 5e existed only for a short period of time.

Just tips about moving wires through walls, please. Thanks again.
posted by Flunkie at 5:05 PM on August 24, 2014

I ran CAT6 in the house a few years back. Totally worth it, relatively cheap to do and was a huge help with connectivity in the opposite end of our Ranch style house. I play a few online games and the lag was an issue since my PC was at the opposite end of where the modem/router are.

The cable you have are most likely not attached to anything, but cable will snag on just about anything. My dad (also a tech junkie) helped me with wiring my house and we had some push/pull moments when the fresh cable we ran got hung on corners, studs, you name it. IT just takes a little finesse and some patients. We used a metal snake, because we were running new cable where no cable was before. Assuming you securely fasten your existing cable and use it as a snake, it should be much easier for you.

If the cables are for some reason stapled down (again, highly unlikely) your best option is to just cut the existing ones at the gangbox and run new cable in the same spot as the old cable. For my house we ran the cable across the length of the house in the attic, drilled holes down for the drop and cut holes in the sheet rock where we put the gang box. It sounds like you wont have to do much cutting, and the holes will already be there, so 2/3rds of the work is done for you. This project took an entire Saturday, so you'll be much better off.

I would offer this advice:

If you plan to be where you are for some time, it would be worth it to put in PVC pipe along where you plan to run the cable. If you ever run new cable it will be PAINLESS to replace the existing cable. It is more work initially but makes repeat jobs an absolute breeze. I wish I would have done it myself.
posted by Twain Device at 5:13 PM on August 24, 2014 [1 favorite]

You can't simply replace cat 5 with cat 6 as the cat 6 spec specifies a lot of installation details like minimum bend radius, so it won't be a "real" cat 6 installation. Also, some of the cable is probably stapled down, but I guess you won't know until you try.

Also, unless you have a need for room-to-room gigabit, you won't get much improvement from cat 6. And if it's installed wrong, it won't give any better performance than cat 5.
posted by GuyZero at 9:19 PM on August 24, 2014

Definitely do this, and your plan is spot on. Wireless sucks in general; it's lossy, prone to interference, and slow, and I'm pretty sure we wouldn't use it if it weren't so dang convenient.

Overlap the cables by 6-12" and when you tape them together, rather than just connecting them end to end. Tape the leading edge of the new cable such that it's, well, aerodynamic, for lack of a better term; you want the junction of two cables to be able to slide past any obstacles as if they were a single smooth cable. If you can think of any reason you should pull two cables through there (Add phone connections, or redundant cables), go ahead and do it now, same rules apply. Another option is a nylon pull string. You can run it into the wall alongside your new cable, and the next person who needs to pull cable through (which might be you) will thank you.

If you do buy the spool (which I also recommend-- you can always sell off the remainder), consider getting plenum-grade cable. The plastic insulation is made to emit less smoke, and less toxic smoke, in the event of fire. Generally not needed for in-wall stuff, where so-called riser- or PVC-cable is used, but required in the US for the plenum spaces, and IMO a good idea for home use, walls or not. Plenum usually has a tougher insulation which means smoother running against obstacles. Buuuut it costs over twice as much. Keeping in mind whether or not you'll sell off the balance of your cable, there's no harm in making the cost choice here.
posted by Sunburnt at 9:52 PM on August 24, 2014

I'd suggest using the old wire to get a "pull string" through the walls first. ie don't use the wire to pull another wire. Using string and knots you can get a much stronger bond between a wire and a string than if you used 2 wires due to the wires having slippery insulation.

Plus you get a slimmer bundle with string. Here's a video showing what I mean. If you can use flat pull tape, it's available at many industrial electrical supply stores. Like Muletape. It's even lubricated to slip better.

You can also get a magnetic system called the Magnepull. You attach a neodymium magnet onto the end of the wire and then a second magnet is rolled along the wall to draw the wire along. I used it once to get a wire from the basement to the floor upstairs. You have to drill small (3/4") holes at the floor and ceiling but they are small and can be easily patched. Not the greatest demo but gives you the idea. Firestops or cross blocks in the walls may make this difficult/impossible though.
posted by Zedcaster at 10:33 PM on August 24, 2014

Not a paid ad but if you haven't already bought it, buy your bulk cable (and heads, and crimpers) from They are insanely cheap and very high quality.
posted by ostranenie at 12:22 AM on August 25, 2014 [1 favorite]

If using the existing cable to pull the new cable goes wrong (like it did at my house recently) and you end up with having to pull the old cable out, try using a vacuum cleaner on one end of the tube and string with a bit of toilet paper inserted into the other - it should suck the string down the tube and you can pull your new cable through with that string.

If you do have trouble pulling the cable through (make sure there are no snagging angles where the string connects to the new cable) try using a lubricant. There are specific cable lubricants (which lubricate but do not erode the plastic cable casing) but if you just squirt quite a bit of washing up liquid in the hole, that should help you out. I wish I had known that when I was pulling as hard as I could to get the GODDAMNED wire down the tube. My theory being, if it doesn't work using brute force, you're not using enough!
posted by guy72277 at 2:34 AM on August 25, 2014

Why on earth would you rip out cat 5 cabling? Are you planning to run 10G to your bedroom? (Hint: no you are not)

This whole plan sounds like it was thought up to solve a problem that doesn't exist, by a person who is under the mistaken impression that running cable is fun.
posted by ryanrs at 3:48 AM on August 25, 2014 [5 favorites]

I agree with the comments that you won't see any difference between cat 5e and cat 6 cables. Maybe try running a cat6 cable through the house first, and see if you notice any difference, as a test?
posted by richb at 4:20 AM on August 25, 2014 [2 favorites]

I am an electrician.

I have done some commercial jobs for big resort hotels in my area where we replaced Cat5e wire with Cat6 wire. I have no idea what the difference between this two wires are on the computing end of things, but there must be some difference, because corporate hotels don't do these kinds of projects willy-nilly.

Your plan to pull the wire should work - and that is exactly how an electrician would do it. Well, not exactly. Let me give you a few tips that will help.

1. make two small loops on each wire, locking the loops together, then tape the wires together. IF it hits a snag, and you have to pull hard, the wires might come out from under tape. Making the loops will prevent this. When you are done, you need to cut the loops out. Cat6 wire is damage if it has been folded tightly back on itself like I am suggesting.

2. tape down the wires as tight as possible. try to keep the bugle as small as possible. you might have to pull through tight spaces.

3. use electrical tape, not duct tape. it will hold better, you can tighten it down better, and it has a smoother edge when pulling. plus, it will not leave a sticky mess on the wire when you remove it.

4. get a spool of Cat6, and tie the end to the wire in the wall. You want to have plenty of extra length when you are pulling. You can buy a spool at any electrical supply shop. do not pull cut lengths of cat 6 wire. you have no idea how this wire is run in the wall - it may not be a straight line.

5. if you do hit a snag - do not pull like a madman. That will only damage the wire. You need someone on both ends, and pull back and forth, trying to get past the snag point.

Generally speaking, it wires should pull pretty easily. By code, electricians do not have to staple or secure low voltage wire in the walls, so it should pull freely. but, chances are, you will hit a snag or two. IF you are in a building with an attic or crawl space, you can usually solve this by tracing the wire physically.

If you can not trace the wire (or you do not feel like crawling in the attic) another thing that might help is lube. you can get electrical lube at any supply shop. Pull the wire back to the starting point, and then lube the wire up as it re-enters the wall. That might be enough to help it slip past a snag.

If you can not trace the wire in an attic, and lube is not working, and you MUST replace the wire, then you need to start cutting holes in the wall. And that can be a mess.

Good luck.
posted by Flood at 5:47 AM on August 25, 2014 [6 favorites]

I have no idea what the difference between this two wires are on the computing end of things, but there must be some difference

You don't have to make guess based on the behaviour of a hotel - go look it up. It's easy to find. Unless you want to run 10Gb ethernet, there is no difference.
posted by GuyZero at 7:19 AM on August 25, 2014

Yes, your plan should work -- but be careful how hard you pull. If you look inside Ethernet cable, you'll see it's a bunch of small wires twisted around each other. Those twists are not arbitrary; they are a specific distance apart for a reason. If you stretch the cable, it messes up those twists and the cable won't work. I was running Ethernet through a conduit that had other wires and a tight corner in it; it took three tries, being extremely gentle the last try, before I could get the Ethernet to work properly because I was stretching it too much when pulling it around the tight corner. I like the suggestion of the person who said to do it in two steps: use the old cable to pull a string through, then use the string to pull the new cable. Hopefully there's no tight 90-degree bends; that can mess up the 'twist' too, rendering the cable nonfunctional.

Also, note that there is "plenum" and "non-plenum" cable. Plenum cable is more fire-resistant, otherwise the same functionally as non-plenum cable. I'd recommend making sure you get plenum cable.
posted by AzraelBrown at 8:02 AM on August 25, 2014

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