reccomendations for flexible 24 AWG cable?

[Michael Noone]

Hi - I need to run 5 24AWG wires to a circuit board that is moving in two
different dimensions. In the future I hope to switch to flex cable for this
job, but right now I'm going to have to stick with normal stranded wire.
I'm hoping for as long of life as possible on these cables, knowing full
well that they will wear out after some time and need to be replaced. I
could either run 5 individual wires or one 5 or more conductor cable. I'm
not sure which would offer the better results. So - my question is this:

What will give me the best results in terms of flexibility and longevity?
I'm wondering both about using 1 cable or 5 individual wires and particular
types/brands/models of cable. I don't think price will be a concern - but
just in case I should mention that my budget is that I want to be able to
buy 5' or so of cable for under $50. Most of what I've been looking at is
in 100' spools for around $30 or so.

Any suggestions? I'm hoping for something that I can pick up at Digi-Key or
Mouser.

Thanks in advance for your help,

-Mike

 

[Pooh Bear]

Hi - I need to run 5 24AWG wires to a circuit board that is moving in two
different dimensions. In the future I hope to switch to flex cable for this
job, but right now I'm going to have to stick with normal stranded wire.
I'm hoping for as long of life as possible on these cables, knowing full
well that they will wear out after some time and need to be replaced. I
could either run 5 individual wires or one 5 or more conductor cable. I'm
not sure which would offer the better results. So - my question is this:

What will give me the best results in terms of flexibility and longevity?
I'm wondering both about using 1 cable or 5 individual wires and particular
types/brands/models of cable. I don't think price will be a concern - but
just in case I should mention that my budget is that I want to be able to
buy 5' or so of cable for under $50. Most of what I've been looking at is
in 100' spools for around $30 or so.

Any suggestions? I'm hoping for something that I can pick up at Digi-Key or
Mouser.

If they stock it, you're best off with 'test lead' style wire. Multiple very
small strands that are less troubled by regular flexing and a soft compliant
insulation ( maybe silicone based ). To be honest I don't know if this is
regularly available in such a small gauge as 24 but worth trying.

Graham

 

[Michael Noone]

If they stock it, you're best off with 'test lead' style wire.
Multiple very small strands that are less troubled by regular flexing
and a soft compliant insulation ( maybe silicone based ). To be honest
I don't know if this is regularly available in such a small gauge as
24 but worth trying.

Graham

Looking at Digi-Key they have some 22AWG test lead wire, such as W2722B-
100-ND (see http://dkc3.digikey.com/PDF/T061/1489.pdf). My worry is that
I'm using Molex 50212-8100 crimp terminals
(http://www.molex.com/customer.html?supplierPN=502128100) which are rated
for 24-30AWG in a 2mm pitch Molex 35507-0500 crimp housing
(http://www.molex.com/customer.html?supplierPN=355070500)

These cables will be put together by hand in low quantities. Though with
normal wire I think I might be able to fudge the rated size for the cable a
bit more - in this case I'm noticing that the outer diameter of the cable
is 2.54mm, while the Molex crimp housing is 2mm pitch. Probabaly more than
can be fudged. Mouser seems to also have 22AWG test leads but nothing
finer.

Though it does make me remember soething from a while back - I put together
a breakout cable for an industrial power supply with a fairly fine pitched
connector using test lead wire. To get the insulation inside the crimp I
ended up shaving off some of the outer insulation. Maybe that would be a
solution for this?

Thanks,

-Mike

 

[Pooh Bear]

Looking at Digi-Key they have some 22AWG test lead wire, such as W2722B-
100-ND (see http://dkc3.digikey.com/PDF/T061/1489.pdf).

Yup. That's the stuff.

My worry is that
I'm using Molex 50212-8100 crimp terminals
(http://www.molex.com/customer.html?supplierPN=502128100) which are rated
for 24-30AWG in a 2mm pitch Molex 35507-0500 crimp housing
(http://www.molex.com/customer.html?supplierPN=355070500)

These cables will be put together by hand in low quantities. Though with
normal wire I think I might be able to fudge the rated size for the cable a
bit more - in this case I'm noticing that the outer diameter of the cable
is 2.54mm, while the Molex crimp housing is 2mm pitch. Probabaly more than
can be fudged. Mouser seems to also have 22AWG test leads but nothing
finer.

OK, the o/d seems to be a problem. The cable is 'too big' !

Though it does make me remember soething from a while back - I put together
a breakout cable for an industrial power supply with a fairly fine pitched
connector using test lead wire. To get the insulation inside the crimp I
ended up shaving off some of the outer insulation. Maybe that would be a
solution for this?

Tricky.

I've seen tiny flex that used silicone insulation that had a smaller o/d. May
be worth searching elsewhere.

Graham

 

[John Popelish]

Hi - I need to run 5 24AWG wires to a circuit board that is moving in two
different dimensions. In the future I hope to switch to flex cable for this
job, but right now I'm going to have to stick with normal stranded wire.
I'm hoping for as long of life as possible on these cables, knowing full
well that they will wear out after some time and need to be replaced. I
could either run 5 individual wires or one 5 or more conductor cable. I'm
not sure which would offer the better results. So - my question is this:

What will give me the best results in terms of flexibility and longevity?
I'm wondering both about using 1 cable or 5 individual wires and particular
types/brands/models of cable. I don't think price will be a concern - but
just in case I should mention that my budget is that I want to be able to
buy 5' or so of cable for under $50. Most of what I've been looking at is
in 100' spools for around $30 or so.

Any suggestions? I'm hoping for something that I can pick up at Digi-Key or
Mouser.

Thanks in advance for your help,

I was just scanning multi conductor cable in the Newark Inone catalog,
Friday, and came across a version by Belden called "FleXnake" that
they sell by the foot. You may want to strip the outer sheath off if
the cable is too large. But the insulation is very flexible and the
wire is highly stranded. They make a 5 conductor, unpaired,
unshielded version. Unfortunately, even though this is a registered
trademark, the keyword "FleXnake" does not bring up any results on
Newark's search engine. But several pages in the catalog are devoted
to the multi conductor, multi pair, shielded and non shielded
variations both on rolls and by the foot. I think the price was about
a dollar per conductor foot.

 

[John Popelish]

Hi - I need to run 5 24AWG wires to a circuit board that is moving in two
different dimensions. In the future I hope to switch to flex cable for this
job, but right now I'm going to have to stick with normal stranded wire.
I'm hoping for as long of life as possible on these cables, knowing full
well that they will wear out after some time and need to be replaced. I
could either run 5 individual wires or one 5 or more conductor cable. I'm
not sure which would offer the better results. So - my question is this:

What will give me the best results in terms of flexibility and longevity?
I'm wondering both about using 1 cable or 5 individual wires and particular
types/brands/models of cable. I don't think price will be a concern - but
just in case I should mention that my budget is that I want to be able to
buy 5' or so of cable for under $50. Most of what I've been looking at is
in 100' spools for around $30 or so.

Any suggestions? I'm hoping for something that I can pick up at Digi-Key or
Mouser.

It looks like the industrial high flex control cable made by Belden is
trademarked, "Infinity". The FleXnake kind may be just audio cable.

It is supposedly rated for 9 million of some kind of flex cycles.
Here is a data sheet for the 9 conductor version, 20 ga, .02"
conductor insulation thickness.
http://bwccat.belden.com/ecat/pdf/7105A.pdf
The Newark part number for the by the foot version is 16F9470.

 

[Richard H.]

What will give me the best results in terms of flexibility and longevity?
I'm wondering both about using 1 cable or 5 individual wires and particular
types/brands/models of cable.

Michael,

How about Cat5 Ethernet patch cable? It's 24AWG, fairly robust, 8
conductor, easily had for <$10. Rough measurements from a couple samples:

Cable OD: 0.210"; conductor OD: 0.036" (7x 0.0043" strands)
Cable OD: 0.200"; conductor OD: 0.032" (7x 0.0033" strands)

Cable flexibility varies, so you're better off buying where you can
check it in person. E.g., the first one listed is more pliable and
loosely jacketed; it's made by Berk-Tek. The individual strands are not
as pliable as probe wire.

It's pretty rare to see an Ethernet patch cable fail under regular use
even in dynamic environments (highly mobile / shared use), excepting
RJ-45 connector tabs and physical abuse. But, they don't see truly
high-volume movement, and the connector is crimped to the cable jacket
for strain relief.

Do you have options for strain relief, such as fastening the cable to
the PCB? Or maybe hot-gluing the back-end of the connector to relieve
strain on the individual conductors at the edge of the crimp? That's
where I'd be most concerned about a failure.

Cheers,
Richard

 

[Michael Noone]

It looks like the industrial high flex control cable made by Belden is
trademarked, "Infinity". The FleXnake kind may be just audio cable.

It is supposedly rated for 9 million of some kind of flex cycles.
Here is a data sheet for the 9 conductor version, 20 ga, .02"
conductor insulation thickness.
http://bwccat.belden.com/ecat/pdf/7105A.pdf
The Newark part number for the by the foot version is 16F9470.

The infinity series looks like a good fit. Belden part number 7200A is a 6
conductor (3x2 twisted pairs) 24AWG shielded cable - looks just about
perfect. Now I have to find a distributor - which is proving to be rather
challenging! Waiting on a couple companies to call me back.

-Mike

 

[Michael Noone]

Michael,

How about Cat5 Ethernet patch cable? It's 24AWG, fairly robust, 8
conductor, easily had for <$10. Rough measurements from a couple
samples:

Cable OD: 0.210"; conductor OD: 0.036" (7x 0.0043" strands)
Cable OD: 0.200"; conductor OD: 0.032" (7x 0.0033" strands)

Cable flexibility varies, so you're better off buying where you can
check it in person. E.g., the first one listed is more pliable and
loosely jacketed; it's made by Berk-Tek. The individual strands are
not as pliable as probe wire.

It's pretty rare to see an Ethernet patch cable fail under regular use
even in dynamic environments (highly mobile / shared use), excepting
RJ-45 connector tabs and physical abuse. But, they don't see truly
high-volume movement, and the connector is crimped to the cable jacket
for strain relief.

Do you have options for strain relief, such as fastening the cable to
the PCB? Or maybe hot-gluing the back-end of the connector to relieve
strain on the individual conductors at the edge of the crimp? That's
where I'd be most concerned about a failure.

Cheers,
Richard

Hi Richard - Ethernet cable was originally my plan, especially since
originally I thought I needed 8 conductors. Problem is at least all the
ethernet cable I have is fairly stiff, even the stranded stuff. I use
some fairly high end patch cable at work, and even that is decidedly
stiffer than I'd like. Ideally I'd like this cable to be like a wet
noodle. But if the Belden cable John reccomended doesn't pan out I
probabaly will end up with patch cable.

-Mike

 

[Rich Grise]

Hi Richard - Ethernet cable was originally my plan, especially since
originally I thought I needed 8 conductors. Problem is at least all the
ethernet cable I have is fairly stiff, even the stranded stuff. I use
some fairly high end patch cable at work, and even that is decidedly
stiffer than I'd like. Ideally I'd like this cable to be like a wet
noodle. But if the Belden cable John reccomended doesn't pan out I
probabaly will end up with patch cable.

-Mike

How about that telephone-cord style stuff, but 6-conductor? (or 8, you
can leave a few open or maybe have a couple of spare grounds or
whatever). The "ethernet" cables I've seen all have solid wire, which
would fail in a matter of weeks in a flex setting.

Or even two ordinary telephone cords?

Good Luck!
Rich

 

[JeffM]

How about that telephone-cord style stuff, but 6-conductor?

Rich Grise

Have you ever tried to work with "tinsel wire"
outside its specified connectors? Not fun.

 

[Spehro Pefhany]

Have you ever tried to work with "tinsel wire"
outside its specified connectors? Not fun.

I vaguely remember trying to work with one of those big crystal
earbuds wot had flimsy flesh-colored (insert standard inclusiveness
disclaimer) twisted tinsel wires.


Best regards,
Spehro Pefhany