Hi all,

Can anyone give tips on repairing such cables?

In the past all I have done is strip back the insulation, twist each
inner copper pair together and insulate each pair, and then the whole
lot with electrical tape.

The problem with this is that once a pair is twisted together, I have
to bend the twist back against itself in order to lie flush against the
wire (ie when I twist them, the twist is perpendicular to the run of
the wire). This doesn't seem good practice somehow, so I wondered what
the correct way to repair such things was.

Also, any advice on stuff like USB cables which have thin metal
shielding running just inside the outer insulation? Will lack of
shielding in the repaired section cause problems?

Thanks,
Lister

Can anyone give tips on repairing such cables?

In the past all I have done is strip back the insulation, twist each
inner copper pair together and insulate each pair, and then the whole
lot with electrical tape.

The problem with this is that once a pair is twisted together, I have
to bend the twist back against itself in order to lie flush against
the wire (ie when I twist them, the twist is perpendicular to the run
of the wire). This doesn't seem good practice somehow, so I wondered
what the correct way to repair such things was.

Also, any advice on stuff like USB cables which have thin metal
shielding running just inside the outer insulation? Will lack of
shielding in the repaired section cause problems?

Repairing any screened cable ifs difficult and is unlikely to be
satisfactory in the long term. USB cables, particularly USB are very well
screened which is one reason they can carry data much faster than USB 1.
Buy a new one.

Peter Crosland

wrote:
Hi all,

Can anyone give tips on repairing such cables?

In the past all I have done is strip back the insulation, twist each
inner copper pair together and insulate each pair, and then the whole
lot with electrical tape.

The problem with this is that once a pair is twisted together, I have
to bend the twist back against itself in order to lie flush against the
wire (ie when I twist them, the twist is perpendicular to the run of
the wire). This doesn't seem good practice somehow, so I wondered what
the correct way to repair such things was.

It doesn't really matter.

Soldering, then insulating can leave a neater join.

Also, any advice on stuff like USB cables which have thin metal
shielding running just inside the outer insulation? Will lack of
shielding in the repaired section cause problems?

Usually it'll work - mostly.
However, for high speed stuff - USB2/firewire/ and the like, it may
well be very unreliable. Or just marginal, and stop working for no
apparent reason in a few months.

wrote in message
ups.com...
Hi all,

Can anyone give tips on repairing such cables?

In the past all I have done is strip back the insulation, twist each
inner copper pair together and insulate each pair, and then the whole
lot with electrical tape.

The problem with this is that once a pair is twisted together, I have
to bend the twist back against itself in order to lie flush against the
wire (ie when I twist them, the twist is perpendicular to the run of
the wire). This doesn't seem good practice somehow, so I wondered what
the correct way to repair such things was.

Also, any advice on stuff like USB cables which have thin metal
shielding running just inside the outer insulation? Will lack of
shielding in the repaired section cause problems?

In general, I'd recommend you replace rather than repair. However, if you
must repair, use a length of "heat shrink" before you strip the two parts
and lay the conductors side by side and solder. Slip the heat shrink over
the joint and heat to shrink.

For screened cables, fold back the screen, treat repair as able, then fold
screen back over the heat shink. Make sure the screen overlaps well and use
more heat shrink.

However, these are temporary / emergency approaches in my view.
--
73
Brian, G8OSN
www.g8osn.org.uk

Now your amateur licence is free, why not send at least £15 per year to
support the
Radio Communications Foundation or STELAR?

wrote in message
ups.com...
Hi all,

Can anyone give tips on repairing such cables?

In the past all I have done is strip back the insulation, twist each
inner copper pair together and insulate each pair, and then the whole
lot with electrical tape.

The problem with this is that once a pair is twisted together, I have
to bend the twist back against itself in order to lie flush against the
wire (ie when I twist them, the twist is perpendicular to the run of
the wire). This doesn't seem good practice somehow, so I wondered what
the correct way to repair such things was.

Also, any advice on stuff like USB cables which have thin metal
shielding running just inside the outer insulation? Will lack of
shielding in the repaired section cause problems?

Probably the *most* correct way of repairing them, is not to. If you can
replace the run of cable with a new run, then that would be the best choice
for safety, mechanical strength and reliability.

-- JJ

wrote:
Hi all,

Can anyone give tips on repairing such cables?

In the past all I have done is strip back the insulation, twist each
inner copper pair together and insulate each pair, and then the whole
lot with electrical tape.

The problem with this is that once a pair is twisted together, I have
to bend the twist back against itself in order to lie flush against the
wire (ie when I twist them, the twist is perpendicular to the run of
the wire). This doesn't seem good practice somehow, so I wondered what
the correct way to repair such things was.

Also, any advice on stuff like USB cables which have thin metal
shielding running just inside the outer insulation? Will lack of
shielding in the repaired section cause problems?

Thanks,
Lister

take each strain, and slip a bit of heat shrink over one of the ends to
be joined, and twist together 'in line' and SOLDER. then use the
heatshrink to insulate the individual strands, and tape the whole lot up
afterwards

Twisting wires together is not good practice - corrosion generally gets
you in the end.

Peter Crosland wrote:
Can anyone give tips on repairing such cables?

In the past all I have done is strip back the insulation, twist each
inner copper pair together and insulate each pair, and then the whole
lot with electrical tape.

The problem with this is that once a pair is twisted together, I have
to bend the twist back against itself in order to lie flush against
the wire (ie when I twist them, the twist is perpendicular to the run
of the wire). This doesn't seem good practice somehow, so I wondered
what the correct way to repair such things was.

Also, any advice on stuff like USB cables which have thin metal
shielding running just inside the outer insulation? Will lack of
shielding in the repaired section cause problems?

Repairing any screened cable ifs difficult and is unlikely to be
satisfactory in the long term. USB cables, particularly USB are very well
screened which is one reason they can carry data much faster than USB 1.
Buy a new one.


The actual effect of a short length on unscreened is not great.
Especially if you wrap it with wire or something conductive afterwards
to 'repair' the screening.

A lot depends on what sort of cable it is: If the screening is to reduce
interference, then that is more than good enough. If it is an RF cable
then you will get small reflections off the join, and this will lead to
slight gain variations with the wire length and frequency. In non
critical applications that is not a big problem. In critical ones it may
be. I wouldn't for example care to do that to a satellite down lead.


Peter Crosland

wrote in message
ups.com...
Hi all,

Can anyone give tips on repairing such cables?

In the past all I have done is strip back the insulation, twist each
inner copper pair together and insulate each pair, and then the whole
lot with electrical tape.

The problem with this is that once a pair is twisted together, I have
to bend the twist back against itself in order to lie flush against the
wire (ie when I twist them, the twist is perpendicular to the run of
the wire). This doesn't seem good practice somehow, so I wondered what
the correct way to repair such things was.

Also, any advice on stuff like USB cables which have thin metal
shielding running just inside the outer insulation? Will lack of
shielding in the repaired section cause problems?

Thanks,
Lister

As you say, not good practice, but it works fine, and my floorboards
conceal several such bodges.
--

Graham.
%Profound_observation%

The Natural Philosopher wrote:

A lot depends on what sort of cable it is: If the screening is to reduce
interference, then that is more than good enough. If it is an RF cable
then you will get small reflections off the join, and this will lead to
slight gain variations with the wire length and frequency. In non
critical applications that is not a big problem. In critical ones it may
be. I wouldn't for example care to do that to a satellite down lead.

USB 2.0 at 480 Mbps would be well into "RF" I would have thought!

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

wrote:
Hi all,

Can anyone give tips on repairing such cables?

In the past all I have done is strip back the insulation, twist each
inner copper pair together and insulate each pair, and then the whole
lot with electrical tape.

Thanks,
Lister

You make it sound as if this a frequent occurrence as far as you're
concerned! Can't you fix whatever is causing the problem?

Cables which are twisted or screened are made that way for a reason and
it is best to either replace the cable or fit the correct connectors
and couplers to maintain the integrity of the cable. They will also
give you peace of mind if they are hidden!

An exception here is telephone wiring as the twist is minimal over a
short distance and signal frequencies are low (unless your running ADSL
over it!)

You might not be so lucky with CAT 5E Ethernet cables though!

Terry

formulated on Sunday :
Hi all,

Can anyone give tips on repairing such cables?

In the past all I have done is strip back the insulation, twist each
inner copper pair together and insulate each pair, and then the whole
lot with electrical tape.

The problem with this is that once a pair is twisted together, I have
to bend the twist back against itself in order to lie flush against the
wire (ie when I twist them, the twist is perpendicular to the run of
the wire). This doesn't seem good practice somehow, so I wondered what
the correct way to repair such things was.

Also, any advice on stuff like USB cables which have thin metal
shielding running just inside the outer insulation? Will lack of
shielding in the repaired section cause problems?

Thanks,
Lister

Rather than twisting them at right angle to the cables, you could do an
in line splice. Put one end along side the other without bending them,
so that the two ends face towards the far end of its opposite number,
then twist them, even better add a small blob of solder to the joint to
make it more reliable.

If jointing more than one wire, space the joints out such that none is
next to another one. A single layer of tape is usually enough to
insulate between cores, then a layer or two over the top of all of
them.

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Owain wrote:

(American site: ignore where it says "Wire nuts are acceptable for home
applications")

Thats nuts, wire they recommending that?

NT

John Rumm wrote:
The Natural Philosopher wrote:

A lot depends on what sort of cable it is: If the screening is to
reduce interference, then that is more than good enough. If it is an
RF cable then you will get small reflections off the join, and this
will lead to slight gain variations with the wire length and
frequency. In non critical applications that is not a big problem. In
critical ones it may be. I wouldn't for example care to do that to a
satellite down lead.

USB 2.0 at 480 Mbps would be well into "RF" I would have thought!

Yes, but its a lot higher power. A bit of loss here and there won't make
it too bad.

Its when your data is encoded into very subtle variations in phase that
you get into trouble. You probably don;t even WANT to examine how a DSL
modem works...