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The difference between wrapped and extruded wire?


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Hello! I apologize for being a little off topic here, but rather than having to register on a new site and ask elsewhere, I figured I'd take a chance and ask here...

 

I'm working on a wiring harness in Autodesk inventor, but I need to add a custom list of wires to the cable & harness library, with a format which is consistent with the Standard for PTFE Insulated Wire. For example, "HP3 - EEXBGE9. One of the specifications involved is "construction type," and apparently my options are "wrapped" or "extruded," but I have no idea what the difference is between them.

 

I've tried google searching, and we've purchased the full standard and I still can't find a thorough explanation. Can anyone please describe for me the differences? Can one tell the difference by visual inspection? Are there pro's and con's associated with the two construction types?

 

Thanks in advance for your assistance.

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This will be a WAG, but -

 

 

 

PTFE = Polytetrafluoroethylene

 

Extruded - the wire run through a die with the plastic tube hot-extruded around the wire as a cylinder.

Wrapped - the plastic in tape form and wrapped around the wire and seam sealed (this is the WAG).

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This site explains Tape Wrapped Sintered construction.:http://www.druflon.com/twswires.html

 

JD was very close. The TWS wire is wrapped and then passed through an oven to fuse the wrapping. This method makes the wire easier to strip, as the PTFE does not creep between the strands of the conductor.

 

Extruded insulation is as he explained. Unless extreme care is taken, the wire can get off center in this method of construction, where tape wrapping prevents that.

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Thank you for the replies, gentlemen! Jack_O'neill, Daniel Jackson would be proud; that website was a great find!

 

Thanks again!

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Thank you for the replies, gentlemen! Jack_O'neill, Daniel Jackson would be proud; that website was a great find!

 

Thanks again!

:rofl: thanks...happy to help.

 

My last full time employer was an electronics manufacturer that also built cable assemblies. I've spent a considerable amount of time pouring over specs on wire looking for types that would do what the customer wanted and meet production and safety requirements. TWS was in most cases much easier for us to work with because the conductor stayed centered in the insulation. Our cutting and stripping machine would struggle with the extruded versions at times. We'd get nicked conductors, and it would have difficulty pulling the ends off at times. Then again, you get what you pay for. The better quality extruded types are naturally more expensive, but they don't have those problems. You just have to use which ever is appropriate for the application.

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I have a new question regarding wire specifications:

 

I understand wire guages are used to specify the size of the conductors with respect to the amount of current they can safely handle through them, but I noticed this PTFE standard gives options for choosing "Insulated Conductor Size Diameter." For example, for an AWG #6 wire, I have a choice between 0.286 and 0.301. If the "Nema type," "construction," "conductor material,"AWG size," and "stranding" are already determined, how can we change the conductor size diameter without also changing other predetermined specifications?

 

I always assumed the conductor size diameter would be a set value (unable to change without also changing the AWG size and/or conductor material and/or stranding) based on the conductor material, AWG size and stranding.

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I have a new question regarding wire specifications:

 

I understand wire guages are used to specify the size of the conductors with respect to the amount of current they can safely handle through them, but I noticed this PTFE standard gives options for choosing "Insulated Conductor Size Diameter." For example, for an AWG #6 wire, I have a choice between 0.286 and 0.301. If the "Nema type," "construction," "conductor material,"AWG size," and "stranding" are already determined, how can we change the conductor size diameter without also changing other predetermined specifications?

 

I always assumed the conductor size diameter would be a set value (unable to change without also changing the AWG size and/or conductor material and/or stranding) based on the conductor material, AWG size and stranding.

 

I'm sorry, where are you seeing that it gives you a choice? The size table in the link I posted says AWG 6 is 0.361 diameter.

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I'm sorry' date=' where are you seeing that it gives you a choice? The size table in the link I posted says AWG 6 is 0.361 diameter.[/quote']

 

I've been instructed to design all wires with exact reference to the "NEMA standard publication HP 3-2001." This standard, on page 11, contained within Table 3-1 (Diameters of Insulated Conductors) listed two insulated conductor size diameters (a min. and max.) corresponding to the 6AWG wire. The reason I believe I need to better understand these specifications is because in Autodesk Inventor, while adding custom wires to the Cable & Harness Library, one of the required fields is called "Outer Diameter."

 

Note: I would also include an image of the standard where it shows two conductor size diameters, but don't want to break any copyright laws.

 

 

Size Diameter.JPG

Edited by AutoNub
Substituted image with attachment and added details.
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oK, gotcha. first, I misquoted a bit ago...the .361 I mentioned as diameter was strand diameter in mm. Looking at the wrong column...sorry.

 

I don't know anything at all about Inventor, so I'll defer the folks that do on Inventor specific questions, but I would suggest that if you have a specific manufacturer in mind, enter the specs from that manufacturer. There are lots of variables that will affect outer diameter other than current. Voltage, frequency, chemical resistance and so forth all come into play. If you can't find a wire in the library that you need, I'd enter the specs from the catalog for the wire I was going to use. The minimum and maximum you refer to specify a range that the wire can be and still be called AWG 6. It can be as small as the minimum, and up to as large as the maximum.

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After looking at the Sleeves/Tubings Size Table versus the Wires & Cables Conductor Size Table from the site you referenced earlier, I believe the "Outer Diameter" field in the image I provided in my previous post is actually corresponding to the entire wire (conductor and its insulation) diameter. The 0.361 mm diameter you noted before is corresponding to the individual conductor size. Note: 0.361 mm = 0.014212 in. Thus, the outer diameter must be the total diameter of the 133 conductor strands with insulation? So this value is the outer diameter, right? This is my current and was my original assumption. However, I still don't quite understand how the "Insulated Conductor Size Diameter" can vary independent of the other aforementioned specifications. Also, I'm hoping someone can verify for me whether the "Outer Diameter" in Autodesk Inventor is indeed corresponding to the overall diameter of the wire in its entirety (diameter = conductor strands+insulation+minute spacing between strands and insulation).

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I don't have the NEMA standards publication here, the shop I worked for had a copy and I never needed to buy one for home use.

 

The Sleeves and Tubing Size table really doesn't have anything to do with determining wire sizes. Those are actual sleeves and tubing you can put over wires or leads or hoses for protection and reinforcement.

 

The bit about the strand size I mentioned in post 9 was me admitting to reading the wrong column...ignore that and don't let it confuse you.

 

You are correct...outer diameter is just that. The outer diameter of the wire including the insulation.

 

The diameter will vary within the range specified in the book. This is an industry standard manufacturing tolerance. No one on earth can melt plastic and run it the length of a spool of wire and have it be perfect. Even the diameter of the wire will vary as will the diameter of the strands. They don't machine this stuff on a lathe, it's created by pushing/pulling copper through a die to stretch it and reduce its diameter. Stranded wire is then twisted to make the conductor, and variations exist in that as well. It is imprecise at best, and you can't expect it to be perfect, hence the size range. Make your sizes at the nominal, the middle of the range if you will, and that's the best you can hope for. That's just the nature of the beast. It will be somewhere between the bottom and top of the acceptable range. Most manufacturers will hold a tighter tolerance than the national standard, but it still can't be exactly the same size every time.

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The diameter will vary within the range specified in the book. This is an industry standard manufacturing tolerance. No one on earth can melt plastic and run it the length of a spool of wire and have it be perfect. Even the diameter of the wire will vary as will the diameter of the strands. They don't machine this stuff on a lathe' date=' it's created by pushing/pulling copper through a die to stretch it and reduce its diameter. Stranded wire is then twisted to make the conductor, and variations exist in that as well. It is imprecise at best, and you can't expect it to be perfect, hence the size range. Make your sizes at the nominal, the middle of the range if you will, and that's the best you can hope for. That's just the nature of the beast. It will be somewhere between the bottom and top of the acceptable range. Most manufacturers will hold a tighter tolerance than the national standard, but it still can't be exactly the same size every time.[/quote']

 

 

There's another perfect response. I do believe you are my new best friend on these forums! Thanks so much for the insight! Just one last question on this subject: are the "outer diameter" values for the default wires in the Cable & Harness Library the averages of the respective min. and max. diameters? I'm wondering how the makers of Autodesk Inventor came up with those values for their diameters.

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.... Also, I'm hoping someone can verify for me whether the "Outer Diameter" in Autodesk Inventor is indeed corresponding to the overall diameter of the wire in its entirety (diameter = conductor strands+insulation+minute spacing between strands and insulation).

 

I would simply make a route and measure it. (nothing like verifying for yourself to build confidence in your model)

If you have a bunch of wires and route or auto-route them through a cable - notice that Inventor automatically resizes the cable based on the combined wire diameters. There should be a tutorial somewhere that shows this happen.

As noted previously in this thread - allow some tolerance - these are not machined "parts".

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.... Also, I'm hoping someone can verify for me whether the "Outer Diameter" in Autodesk Inventor is indeed corresponding to the overall diameter of the wire in its entirety (diameter = conductor strands+insulation+minute spacing between strands and insulation).

 

I would simply make a route and measure it.

If you have a bunch of wires and route or auto-route them through a cable - notice that Inventor automatically resizes the cable based on the combined wire diameters. There should be a tutorial somewhere that shows this happen.

As noted previously in this thread - allow some tolerance - these are not machined "parts".

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  • 2 weeks later...

I have been alerted to this discussion because information from my website has been linked.

 

If I can help, I will welcome members to seek any relevant technical information on the topic of discussion.

 

I would like to make a very minor correction to JD Mather's statement in an earlier post -

 

Extruded - the wire run through a die with the plastic tube hot-extruded around the wire as a cylinder.

Wrapped - the plastic in tape form and wrapped around the wire and seam sealed (this is the WAG).

 

As a general statement about extruded wires this is true, but not about PTFE extrusion. PTFE does not melt, and because melt viscosity of PTFE is very high, it is cold-extruded, unlike PVC and many other insulating plastics. This causes its own unique problems as mentioned in some of the posts by Jack_O'neill.

 

On conductor sizes, insulated wire diameters and conductor temperature rise for given current flowing in it, you will find more information in our website.

 

Regards.

 

Dr. Mukul M. Mittal

 

http://www.druflon.com

 

P.S. Forum software denied me the privilege of using my first name as login name since it views me as a spammer :).

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