Splicing cat.5 cable

[Dave Smith]

My dog chewed up a section of cat.5 cable from my router to a
computer. Really. Now that we've eaten the dog, I have to repair the
damage. The cable is routed through the ceiling of the house and I
REALLY don't want to do that again, so I'm hoping I can just get
another length of cable and splice it to the existing one. Is the
color coding of the wires uniform? If so, can I just solder the wires
together (insulated of course) or is there some reason that approach
won't work. I know there are kits for putting new connectors on
cables, but I'd rather not invest in one for a one time repair.

Thanks very much for any help.

 

[thehick]

The best way would be to put rj-45s on and
use a F-F connector from the dollar store.
but since you don't want to cough up the money
for a one time job, just try it. the worst
that will happen is collisions and hence, lower thruput.
this is why running a spare cable is always
a good idea. especially if the job is a tough one.
....thehick

 

[kony]

My dog chewed up a section of cat.5 cable from my router to a
computer. Really. Now that we've eaten the dog, I have to repair the
damage. The cable is routed through the ceiling of the house and I
REALLY don't want to do that again,

You might be surprised how easy it can be to pull cable,
when you already have an old cable there. By splicing the
end of the old to the new, and pulling the old through, it
pulls the new through, so you then put a connector on each
end. Can't see the specifics of the situation though, if
you say it's not feasible I'll leave it at that.

so I'm hoping I can just get
another length of cable and splice it to the existing one.

.... or where the break is, put a connector on it to
terminate it and a coupler or hub.

Is the
color coding of the wires uniform?

For your purposes, yes. The colored wire plus the white
with same-colored stripe are always twisted pairs. So, to
splice you would simply connect same-colors. However,
you're not supposed to leave these pairs untwisted for more
than about a 1/2", so taking your time and doing a good job
of getting all to the right length, having tight twists of
the bare wires soldered (not just touching bare) and
heatshrinked, then retwisted, is rather important. Leaving
too much untwisted may introduce noise... how much that
effects the run may depend on it's general condition besides
this repaired section.

The question about the colors has another answer though,
that the colors to pin positions in the connector must match
on each end as well and there are two standards for that,
568A & 568B. See the following page and if you don't know
what you have, check continuity with a multimeter if you
can't tell from looking at the (other) end of the existing
wire.
http://www.bluemax.net/techtips/networking/Wiring_Tips/Wiring100TX/colorcodestandards.htm

If so, can I just solder the wires
together (insulated of course) or is there some reason that approach
won't work. I know there are kits for putting new connectors on
cables, but I'd rather not invest in one for a one time repair.

Thanks very much for any help.

It can easily work, mainly you need to be careful to
maintain the same wire lengths and amount of overlap while
twisting them prior to soldering such that they all end up
(at least each two in a twisted pair) close to same length.

Since they're twisted all along, getting the heatshrink or
other insulator on is the next hurdle, doing so and being
able to re-twist them together. If they're solid-core,
they'll be harder to manage and rather than trying to put
individual insulation sleeves on each solder joint, it may
be easier to push back a piece of shrink-tubing over the
pair of wires (so it'd cover both together), then on the
first solder joint of a twisted pair, put a piece of
heat-shrink over that single wire (pushed back out of the
way of soldering heat), then after soldering slide it into
place, THEN before soldering the other twisted pair wire
ends together, wrap them both around the
already-finished-and-heatshrunk wire before soldering.
Lastly slip the heatshrink tubing back down around the pair
to insulate from the remaining wires. I'm sure I didn't
write the above very well but the point is that by not
heatshrinking both individually, you can wrap the second of
each wire-pair around the first not having to slide down the
heatsink tubing after soldering.

 

[Dave Smith]

Thanks very much Kony. I'll frown about this some more and I'm sure
your info will help me get this done.

 

[badgolferman]

My dog chewed up a section of cat.5 cable from my router to a
computer. Really. Now that we've eaten the dog, I have to repair the
damage. The cable is routed through the ceiling of the house and I
REALLY don't want to do that again, so I'm hoping I can just get
another length of cable and splice it to the existing one. Is the
color coding of the wires uniform? If so, can I just solder the wires
together (insulated of course) or is there some reason that approach
won't work. I know there are kits for putting new connectors on
cables, but I'd rather not invest in one for a one time repair.

Thanks very much for any help.

I would avoid trying to splice the cable. The pairs are wound together
so many times within a foot and changing that will affect your signal,
especially since you have run it a long distance.

My first choice would be to rerun a new one, using the old wire as a
pull cord from both directions. My second choice would be to put
either a RJ-45 receptacle plate on one end and a RJ-45 connector plug
on the other end.

 

[RBM]

If you don't care to rerun the cable or screw with rj-45 jacks, you can get
3M telephone wire sealed splicing crimps from Home Depot. No special tools
needed, just match up the colors, push into a crimp and squeeze with a
pliers. You don't even strip the insulation. They're silicone sealed and
last forever

 

[Ken Maltby]

Thanks very much Kony. I'll frown about this some more and I'm sure
your info will help me get this done.

It actually does make sense, if you have ever done it.

I would pull a new cable though. Splicing is not as critical
as some seem to be making it sound, but why bother.

Luck;
Ken

 

[XModem]

Thanks very much Kony. I'll frown about this some more and I'm sure
your info will help me get this done.

If you decide to pull a new cable, and it runs through some tight spots, a
squeeze bottle of Ideal Yellow 77 is worth its weight in gold.
In a pinch, I've seen dishwashing liquid used.

 

[John McGaw]

My dog chewed up a section of cat.5 cable from my router to a
computer. Really. Now that we've eaten the dog, I have to repair the
damage. The cable is routed through the ceiling of the house and I
REALLY don't want to do that again, so I'm hoping I can just get
another length of cable and splice it to the existing one. Is the
color coding of the wires uniform? If so, can I just solder the wires
together (insulated of course) or is there some reason that approach
won't work. I know there are kits for putting new connectors on
cables, but I'd rather not invest in one for a one time repair.

Thanks very much for any help.

And your lan speed is? And your link length is? If you are running
10baseT then go for it, almost any sort of neat splice will work even if
it is a moderately long run. If you are running 100baseT and your run is
short and you can do a _really_ neat splice maintaining a consistent
twist to the cable it will probably work. If you are running gigabit
forget about splicing and pull some new cat-6 cable immediately using
the old cable as a pull string.

Generally, pulling new cable to replace an existing run is far less
painful than pulling the original. Just keep the joint between the old
and new cable small and smooth and it should slide right through a
straight pull. Pull each segment (between the bends) by itself and don't
try pulling around sharp bends and everything should be fine.

 

[Pelysma]

My dog chewed up a section of cat.5 cable from my router to a
computer. Really. Now that we've eaten the dog, I have to repair the
damage. The cable is routed through the ceiling of the house and I
REALLY don't want to do that again, so I'm hoping I can just get
another length of cable and splice it to the existing one. Is the
color coding of the wires uniform? If so, can I just solder the wires
together (insulated of course) or is there some reason that approach
won't work. I know there are kits for putting new connectors on
cables, but I'd rather not invest in one for a one time repair.

Thanks very much for any help.

I would never do this professionally, but in my house I did it.

I ran cable to my garage but don't have a crimping tool, so I cut a 6'
premade cable in half and spliced the halves to both ends of the long cable
run, using a woodburning pencil as a soldering gun. I opened and stripped
as little cable as I could get away with and wrapped each soldered joint
with black plastic electrical tape afterward, then the whole joint.

It's important, of course, not to get any cold joints. Heat the wire, not
the solder, and melt the solder by touching the heated twist of wire.

It works, 100baseT. I consider this an interim situation until I have an
excuse to spend the money for a crimping tool, which is a far better
solution.

 

[VWWall]

My dog chewed up a section of cat.5 cable from my router to a
computer. Really. Now that we've eaten the dog, I have to repair the
damage. The cable is routed through the ceiling of the house and I
REALLY don't want to do that again, so I'm hoping I can just get
another length of cable and splice it to the existing one. Is the
color coding of the wires uniform? If so, can I just solder the wires
together (insulated of course) or is there some reason that approach
won't work. I know there are kits for putting new connectors on
cables, but I'd rather not invest in one for a one time repair.

Easy! Firstly, Ethernet uses only two of the pairs in a CAT-5 cable.
These are usually the orange and green pairs, and these are the only
ones you need to repair.

Start by removing about six inches of the outer jacket from both ends of
the cable. Use a sharp knife, cutting out so as not to nick the inner
wires insulation. Cut two inches off one wire of the orange pair and
two inches of the other wire on the other end of the cable. Strip one
half inch of the insulation from each of the wire ends. Do the same to
the striped orange wires. Now twist the bare ends fo the two solid
orange wires together with pliers, tightly but not so tight as to risk
breaking the conductors. Now wrap the striped orange wires around the
solid orange wire to restore the twist, and twist the bare ends
together. The joints will be separated by about two inches, so they
can't touch. Now, do the same with the green pair, and you're done!

Try it out to make sure you've restored the correct pairs, and then
apply tape insulation to the four joints. Tape the whole cable together
for mechanical protection, laying the un-spliced wires along side. For
good measure you can wrap the whole thing with a layer or two of
aluminum foil for electrical shielding. Not needed, but might
discourage the dog!

This probably introduces less "un-twisted" sections in the cable than
two plugs and a connector. I wouldn't solder the wires, twisted "wire
nuts" have been used in millions of electrical installation at far
higher voltages than this. Just make sure there is no mechanical stress
on the joints. This is better than the many "crimped" joints in added
connectors, especially with an untrained operator and poor crimping
tools, and the cost is zero.

Go for it!

 

[ISOHaven]

Ugh, I am so sick of hearing people grip about splicing cables. That is
such a old garbage wives tale!!!

Take a look at the average cable run.

Point A is attached to a punch down. From the punch down you plug in a
cable and run that to your switch.
Point B is attached to some form of wall plate. From that plate you plug in
a cable and run that to you computer.

So from the switch to your computer you have 2 SPLICES!!!! There is
absolutely nothing wrong with a third splice. Hell, you could even argue
that the connectors going into your NIC and switch are splices themselves.
If you are that worried about it then cut your cable and attach one end to a
wall plate, then plug in the other end to the wall plate since that seems to
be "socially acceptable". Heaven forbid you actually connect the wires
together!

We moved a department about 200 feet and left the old cables. We just
spliced in extentions. All those machines run fine using gigabit
connections.

Do splices degrade the signal? Of course. But not enough to worry about.
Especialy if all your lines already have 2 splices in them.

 

[thehick]

"We moved a department about 200 feet and left the old cables. We
just spliced in extentions. All those machines run fine using
gigabit connections"
You sound like a hacker. Splices are a bad idea because they
get hidden in walls. Plates and other types of connections
are usually very visible. This is for long-term support reasons.
And I shudder when I hear someone say that their network
is good because it "works". It'll could work fine and still
be near failing. I like to hear that tests were run and they passed.

having said that, the OP is talking about a home network,
not a business. It doesn't matter!
....thehick

 

[ISOHaven]

This "department" was a subset of our graphics department. They transfer
many gigs per day. The only test I needed to run was transferring 1GB worth
of files before the move and after the move. The copy took the exact same
amount of time. I do not know what a PING alternative is on a MAC so I
didn't even go there.

Also, pop a single panel from the downstairs dropped ceiling and you have
access to all splices for that department.

 

[kony]

"We moved a department about 200 feet and left the old cables. We
just spliced in extentions. All those machines run fine using
gigabit connections"
You sound like a hacker. Splices are a bad idea because they
get hidden in walls. Plates and other types of connections
are usually very visible. This is for long-term support reasons.
And I shudder when I hear someone say that their network
is good because it "works". It'll could work fine and still
be near failing. I like to hear that tests were run and they passed.

having said that, the OP is talking about a home network,
not a business. It doesn't matter!
...thehick

You are correct that in a business environment it's probably
prodent to just pay someone to string a new cable. However,
if a makeshift cable were implemented and demonstrated to
work, tested to do so as any new cable would need be, too,
then the remaining issue is same as with a new cable, that
if in the future the link is going south that segment will
need tested again.

 

[ISOHaven]

I just threw a laptop up there and ran some ping tests from a few lines.
Results are the same as any other machine with 2 splices. So that third
splice isn't affecting it in anyway. It's been just over a year since the
move.

35,000 <1ms

 

[DaveW]

Just beware in your attempted fix: Cat 5 cable is very finicky about
passing data uncorrupted if it isn't perfect.