Twisted Pair Wire?

[Tress]

I have a Xantrex Link 10 that im about to connect, it requires twisted pair wire and i remember reading somewhere on this forum how to make your own? I'll need 2 pair (4 wires) and im wondering if all I have to do is buy the 4 wires and twist them together and then tape em, or if its more complicated? Could i twist each pair separately then twist them together or do they all have to be twisted together at once? Thanks in advance for any info!

:REOutArchery02:

 

[Clark White]

Never mind, I read up on it some and apparently they are very specific about using twisted pair for noise purposes. If it is that sensitive, then you probably need to buy the TP, you wont be able to get the pitch consistent enough. Still not sure why a battery monitor is so sensitive to internal noise, but apparently it is. Best bet is just to find some good stuff from a store rather then making your own.

Clark

 

[Clark White]

On pg 13 of the manual it does a good job of explaining why it is so sensitive. I was originally assuming it was just plugged into the battery, but it's using a shunt with only mV running through the TP, hence the sensitivity to interference. Given that, I would definitely stick with purchased TP as you wont be able to get the proper consistency in your pitch if you do it your self.

Clark

 

[goodtimes]

I have used a cordless drill and a vice to twist my own. 14 turns per foot should do it (at least it did for the ABS mods I was doing).

 

[ntsqd]

I have used a cordless drill and a vice to twist my own. 14 turns per foot should do it (at least it did for the ABS mods I was doing).

Our previous EE here at work used to do that all the time for our various testing needs.
ecomotors.com
propulsiontech.com

 

[Lynn]

We use the vice/drill method all the time where I work.

Addited: Twist the individual wires into pairs to keep the induced 'noise' down; twist the pairs together into sets if it helps with cable management. For things like high-speed data links you can also add a ferrite bead around the individual data lines.

 

[DaveInDenver]

Add a third to the drill and vice method (and we're doing hi-rel stuff). Too many variables of material, gauge, insulation, intended impedance and operating freq. to stock all possible twisted pairs. An old hand drill works well to minimize potential damage, but if it's a long length a cordless drill is perfect. This is pretty much how they make them at the factory.

You should shoot for about 30 to 50 twists per meter (so around 1 to 2 twists per inch) minimum to impedance couple two wires. Tighter is better, but it does depend on the frequency as to how many twists are absolutely necessary. Generally, 4 to 6 twists per inch is very tightly coupled up into the tens of MHz. But if you are just looking for differential noise immunity for control signals, then 1 twist per inch is fine.

Also if you are bundling several twisted pairs into a cable, each pair should have slightly differing numbers of twists per length to minimize cross coupling of pairs. If you look at bundled UTP network cable, each pair will have a little different twist rate. Also within the bundle, arrange the pairs so the they weave loosely, IOW don't bundle the twisted pairs into a long parallel grouping of pairs. A weaving that has pairs crossing every few inches is fine.

 

[Mike S]

Standard twisted pair or shielded twisted pair?

Personally, I would go buy a quality product and move on with the project. TP is designed and manufactured to telco and IEE specs for transmission reliabiity and I doubt that something fabbed in a garage workshop will either save money or meet specs. IMO, of course.

 

[DaveInDenver]

TP is designed and manufactured to telco and IEE specs for transmission reliabiity and I doubt that something fabbed in a garage workshop will either save money or meet specs. IMO, of course.

Nope, making your own twisted cables is common. Telcos do buy pre-made, that is true. But they are getting 10,000' rolls. Making your own is pretty basic and happens all the time. Spec your wire part number and twists per cm and the techs just make it, nothing fancy. For the important stuff, they have a bench where they twist the pair, dab epoxy on each end and let it cure. If you are just making a twisted pair for noise immunity, drill and vice method is perfectly fine.

 

[Tress]

Great info! Thanks! Sounds like i could prolly make what we need, the run should only be around 8 feet, although i really dont know what the monitor requires with regard to "noise" protection. Once you get the twists you need how do you keep the wire twisted like that? Do you stop and tape every few feet once you have the twists required? Or do you tape it every inch you complete? Thanks a lot for the info... the wire they sell only comes in 25 ft lengths and is around $40

:REOutShootinghunter

 

[goodtimes]

Once the wires are twisted together, they will stay put. No need to tape it together.

If your run is 8' long, start with 12+ feet of each wire. Yes, that is a rough number, but as the wire twists, it will "shrink" considerably. Nothing sucks worse than being 3" to short in an effort to save a bit of wire.

 

[Tress]

Ya thad suk! Bad! Well sounds like we will give it a shot, however I don't have a vice, i suppose i could get one but is there any other way?

:REOutArchery02:

 

[Mike S]

Nope, making your own twisted cables is common. Telcos do buy pre-made, that is true. But they are getting 10,000' rolls. Making your own is pretty basic and happens all the time. Spec your wire part number and twists per cm and the techs just make it, nothing fancy. For the important stuff, they have a bench where they twist the pair, dab epoxy on each end and let it cure. If you are just making a twisted pair for noise immunity, drill and vice method is perfectly fine.

Dave - I must have spent too much ime in the network/telco industry. I don't exactly understand his application anyway.

I have found, though, that cobbling up something myself is not always as satisfactory as buying the right product and getting on with it.

 

[DaveInDenver]

Dave - I must have spent too much ime in the network/telco industry. I don't exactly understand his application anyway.

I have found, though, that cobbling up something myself is not always as satisfactory as buying the right product and getting on with it.

I have limited experience in telecom and what we do where I work now is essentially all one-off (thus, very expensive) custom things, so my outlook is also skewed. But I've been an EE and built DIY audio for about 15 years and have made my own twisted pair a lot.

As far as making it yourself, yeah I totally agree. Sometimes buying the product from the place with the right tooling and experience results in a much better widget. But sometimes doing it yourself is the only way to get a quality anything. So I guess I'm just saying it depends. How's that for non-committal?

Not sure what he's doing either, but the Xantrex Link 10 is a battery monitor, so my assumption was the twisted pair was for noise immunity. Not many other reasons I can think of for doing that on a standalone 12VDC power monitor.

 

[Tress]

Yes the application is for a Xantrex Link 10 Batt monitor, the manual states the monitor requires twisted pair wire for the install but the wire they sell only comes in 25 ft lengths and has 4 pairs in it. The monitor can use all 8 wires but i only require 5 of those 8, plus i only need around 10 feet alltogether so it seemed like a waste to go and buy the one they sell

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