Soldered splices

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iwire said:
A lot of flash and still no direct answer.

You chose to be 'picky' in this thread so I am just being picky with you.

You clearly indicated in post #31 that "the line" would get shorter. Well the 'line' does not get shorter; it is simply in another shape.
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How can I be any more direct than the contact line gets shorter? And it does get shorter. It isn't in a different shape. It's still a line. Only the wire takes a different shape. I have tried to help you understand. If you are going to make comments of this nature, my desire to help you understand will wear thin real quick.

iwire said:
So what was it you where trying to say in post 31?

You don't have to open your graphics program for this question.
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You're right. I don't have to open my graphics program for this question. The answer is: I said what I said and meant exactly what I said. I was not trying to say anything different.
 
Smart $ said:
How can I be any more direct than the contact line gets shorter? And it does get shorter. It isn't in a different shape. It's still a line. Only the wire takes a different shape.
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IMO you are mistaken.

In the real world, outside a PC screen you will find that 'the line' sprials, it does not stay straight.
 
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I would be both with building wire, and other electrical and electronic applications - and plumbing.....

Now, I'm just gonna toss out something I learned, when learning how to solder, and was explained in very simple terms considering what could be some complex math..... When making a good joint, the area of contact should be equal or more than the circumferance of the conductor. As the therory goes - the electrical path in AC is concentrated in the outside circumferance. Depending on the frequencey. Let the debate begin on skin effect elsewhere. According to that, the contact area would only need to be that much...

That "line" which does consitute an "area", would only need to be the same or more than (in length) than the circumferance of the conductor, or largest one for an effective circuit. And if that "line" were 3.14 times the the radius squared it would be equal to the cross-sectional area.... (Which according to that therory, is not totally nessesary...)

http://www.mathopenref.com/arcsector.html

So if the joint (that line - whatever shape) were equal to the cross-sectional area, it would be far greater than the circumferance. (About 6x's roughly)

http://www.mathopenref.com/circumference.html

So if you have 6 wraps, as you would with say a western union with 3 wraps on each side - you would have exceeded the cross-sectional area. And like-wise if you twisted two lengths of wire 6X's it circumferance, or 3.14XR squared..... Mechanically without solder.... That held in a wire nut, or in solder will be about the same resistance of the wire. (But will still show up in a TDR graph as a reflection.)

I know there is more exacting math to this - but hey - its Sunday.... ;)
 
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iwire said:
IMO you are mistaken.

In the real world, outside a PC screen you will find that 'the line' sprials, it does not stay straight.
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I agree the real world introduces condiitons and parameters which I cannot reproduce on the PC. However those conditions and parameters do not introduce any considerable departure to the outcome.


Compare objects in the following image. For a description of the two-part object on the right, see my Post #60 response to rattus.

View attachment 247
 
I'm getting on the bandwagon of dis-agreeing with you in the length of contact area.... Neither of the conductors or area of contact have shrunk at all, just in a helical shape they apprear shorter. And IMO matters little in the context of contact - soldered or not.
 
e57 said:
I'm getting on the bandwagon of dis-agreeing with you in the length of contact area.... Neither of the conductors or area of contact have shrunk at all, just in a helical shape they apprear shorter. And IMO matters little in the context of contact - soldered or not.
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I never said the conductors shrunk. The closest I came to that is when I said the inner side of bent wire compresses, i.e. shortens. That is a fact. Anyone can contend otherwise if they care to, but it simply does not change the fact. The contact length also shortens for two twisted conductors compared to the contact length of the same length of two straight conductors held side by side by mechanical means. It is not my responsibility to ascertain everyone recognizes and accepts fact as fact.
 
Smart $ said:
I never said the conductors shrunk. The closest I came to that is when I said the inner side of bent wire compresses, i.e. shortens. That is a fact. Anyone can contend otherwise if they care to, but it simply does not change the fact. The contact length also shortens for two twisted conductors compared to the contact length of the same length of two straight conductors held side by side by mechanical means. It is not my responsibility to ascertain everyone recognizes and accepts fact as fact.
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And we're disagreeing with you. It's not our responsibility to get you to see that you're wrong, only to keep telling you that you are wrong :)

Perhaps on a computer the contact point is the axial line, but in real life the contact point is a helix, and the length of that helix is the same as the length of the wire. Additionally, copper is malleable and will deform when twisted, increasing the contact area as a result of the deformation. So the actual contact area isn't a line of tangent points along the axis, it's a helical ribbon.

(Edited to add a piccie ...)

ContactSurface.jpg


That is actually two different surfaces. The line up the middle is the axial line. The helical ribbon is where the wires contact each other aside from in the center of the double helix. The image was formed by drawing two wires, both slightly larger than they should have been (so that the 3 dimensional objects would have an intersection), then calculating the intersection of the two objects. It's trivially obvious that the wires have points of contact other that the axial line otherwise there'd be nothing keeping the wires from sliding parallel to the axis, and we all know that a properly twisted pair of wires don't just slide around all the time.
 
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mdshunk said:
Was approached by a new builder to our area that builds "McMansions" of sorts. He reports that they require soldered splices. I've never heard of such in this day and age, but whatever the customer wants. In order to properly bid the prints, it would be helpful to know how much time this adds to each hole. Anyone presently solder splices? How much time does it add? Any tips/products to speed the process in regard to insulating the completed splice? (this customer also requires that all devices and fixtures be pigtailed, which adds to the time)
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I haven't done any solder joints in a very long time. The last ones I did we dipped what we could.
 
tallgirl said:
And we're disagreeing with you. It's not our responsibility to get you to see that you're wrong, only to keep telling you that you are wrong :)
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Keep on telling me, if you all want. It still does not change the fact. While you all are at it, is anyone going to offer other-than-words proof that I'm wrong? Stating I'm wrong just don't get it.

tallgirl said:
Perhaps on a computer the contact point is the axial line, but in real life the contact point is a helix, and the length of that helix is the same as the length of the wire.
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Perhaps that would be true if you twisted wires around a straight one in the center, or twisted three wires and kept them in an equilateral triangle arrangement throughout the twisted length. There are most likely other scenarios where that would be true, but two twisted wires is not one of them.

tallgirl said:
Additionally, copper is malleable and will deform when twisted, increasing the contact area as a result of the deformation. So the actual contact area isn't a line of tangent points along the axis, it's a helical ribbon.
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I agree with this statement. However, the "helical ribbon" is quite narrow (unless twisted under substantial tension or pressure, i.e. substantially more than what one can exert when hand twisting with one pair of pliers) and, most importantly, it is symmetrical.
 
Smart $ said:
Keep on telling me, if you all want. It still does not change the fact. While you all are at it, is anyone going to offer other-than-words proof that I'm wrong? Stating I'm wrong just don't get it.
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Well, now we're getting into something called "The Persistence of Belief", which is the tendency of a person to continue believing something that is wrong, long after they've been shown to be wrong.

I agree with this statement. However, the "helical ribbon" is quite narrow (unless twisted under substantial tension or pressure, i.e. substantially more than what one can exert when hand twisting with one pair of pliers) and, most importantly, it is symmetrical.
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My suggestion then would be to get a pair of 9's that are actually nine inches long. It's quite possible to twist wire past it's elastic deformation point to the point of failure. But that would require you have a pair of 9's that are long enough to develop the torque required to do so. ;)

(Edited to add a missing word ...)
 
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mdshunk said:
For some reason, it strikes a funny bone to read two chicks arguing the math behind two twisted conductors.
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It strikes more than one funny bone here since I am of the masculine gender ;)
 
Hi Marc, Here are some quick solutions for your solder job.
1. Use non-corrosive cored silver solder. (96% coin)
2. Use a 200/300w soldering gun. (Weller 2 speed.)
3. Have cloth and denatured alcohol.
4. Per tallgirl, use '9's to pre-twist parallel pigtails for all outlet connections.
note: Multi-wire BC's required [300.13(B)] anyway.
5. Tin joint lightly. Avoid too much heat.
6. Wipe clean, Trim length for assembling Ideal Tan Twister connector.
7. Stow pigtails in box, do not pre-strip, use indent notch per sw/hot ident.
Most importantly: make sure the installation is local AHJ compliant and is acceptable to GC.

Good Luck.
 
tallgirl said:
Well, now we're getting into something called "The Persistence of Belief", which is the tendency of a person to continue believing something that is wrong, long after they've been shown to be wrong.
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...and just what is it that has shown me to be wrong? Are you certain you're not the object of your claim?


tallgirl said:
My suggestion then would be to get a pair of 9's that are actually nine inches long. It's quite possible to twist wire past it's elastic deformation point to the point of failure. But that would require you have a pair of 9's that are long enough to develop the torque required to do so. ;)
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D213-9NE-CR_ICON.JPG

My tool of choice: Klein Tools, Catalog No. D213-9NE-CR

To twist two solid wires past their elastic deformation point to the point of failure within a short limited length, by hand with a pair of pliers, would require farside stabilization of some sort (with the exception being small gauge copper wire). I'd like to see you take two #12's say 10-12" long, and twist only 1" at the ends past failure while keeping the balance of the wires relatively untwisted and never more than 90 degrees apart, and using only your hands and one pair of 9" pliers...
 
Smart $ said:
...and just what is it that has shown me to be wrong? Are you certain you're not the object of your claim?
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Absolutely. I also own a nice 3D CAD program that allows me to draw pretty pictures of things and check the intersections of objects.

The proof that I'm correct about the point of contact being along two surfaces, one axial and the other helical, is that a pair of twisted conductors aren't free to move with respect to each other parallel to the wires themselves. This means that there must be another point of contact with some component perpendicular to the wires And that point of contact is the helical ribbon image I showed earlier.
 
Smart $ said:
...and just what is it that has shown me to be wrong? Are you certain you're not the object of your claim?
quote]

An act of 'projection', thats one of those - uh - Psychological terms...... BTW you (Smart $) were reffered to as female back in post 59, maybe just to see if you were paying attention, but I guess you missed that. Or maybe it was just to get a sense of who you are other than a "Forum Phantom"....

To prove yourself to the rest of us would be more like it, maybe twist some wire..... Not a CAD program - WIRE. You seem to own a computer and a code book, but do you twist wires together for a living?
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Mark, actually it was something that was said here in the forums (not this thread) that leads me to believe smart is of the female gender, I can't prove or disprove it, but for now I am going to think it's the case.

I don't know if this is the reason she hides in anonymity but I don't see why it would.

Roger
 
Half right:

Half right:

Smart may be half right. In the ideal mathematical case, where the wires are not deformed, contact would be made along a straight line which would be shortened as the wires are twisted.

HOWEVER, in the real world, the wires deform as they are twisted. This creates a contact area which is shaped like a twisted ribbon. The centerline of this ribbon is straight and it does shorten as the wires are twisted. The length of the outer edges remains constant though.

Without doing the math, I have to believe that resistance decreases as the splice is twisted tighter.
 
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