Wire: Fine threads vs Course threads

markz

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Hobby King 10 guage with lots of fine threads of wire
or home hardware 10 guage with a few course threads of wire

HK is nice, has a good feel to the insulation, the strands are fine so you can wipe them up easily, a few strands fall into the carpet and no big deal. The wires hang nicely off the battery and controller and dont get in the way, usually.

Course thread strands I pick up, each and every one. It is stiffer and doesnt have a nice feel. Easier to solder I find then finer thread wire. Easier to dump into a bowl of solder then fine, for an XT. The wires will stick out and get in the way if you dont bend them out of the way. Price wise, much cheaper then HK, because hk you have to wait. Now an interesting note is I have yet to find a fine threaded wire at any electrical supply, the rc stores would have them.

Bought some 10awg wire at H.D. today on the returns rack for 50% off, got 4m for $2cdn, its single conductor and course threads but that got me thinking about H.K. Turnigy wire how there are so many fine threads. It did not take me long to find the answer, sure its more then likely posted somewhere here on E.S. Search term "fine wire course" has 310 matches and 12 pages, hey nothing stuck out so searched on.

Makes sense

https://www.quora.com/What-are-the-best-electrical-wires-those-with-fine-threads-or-those-with-thicker-threads
Ahhh trick question. This question touches on both practical as well as theory.

First let's discuss theory... Electricity travels along the very outer edges of an conductor, this is known as the skin effect. No matter how thick the conductor is, the electrons are only traveling on the outside edge, so the more outside edges ( smaller threads) the more surface for the electrons to travel on. So one could draw the conclusion that many threads will be better.

Now for the Practical ... The more amps required the larger the size of the conductor required to carry it.

So the question becomes which is better, a solid wire or a stranded wire? With all things being equal, the size, the insulation, the ambient temp, there is no difference between stranded and solid conductors. The only real difference is that stranded conductors are much more easier to install in conduit, and even more so when factoring in bends .

The technical answers have already been given, the heuristic answer would be as follow (IMHO):

- Finer Threads for low voltage/amperage usage. Where the wire essentially experiences no heat due to over-loading (think Speaker wires or something similar).

- Thicker Threads for low-medium voltage, but higher amperage usage. Where the wire can experience higher heat due to over-loading.

The finer threads will burn out very quickly if they were used for a circuit that would carry a higher-amperage.

.There is no resistive difference between equivalent gauge solid and stranded wire. At 60Hz, the "skin effect" is negligible. The only difference is that stranded wire is easier to pull around bends, and there are a lot more bends in office wiring.
 
From my experience, 10 AWG course strand wire is smaller in overall diameter then the fine threads of 10 AWG silicone wire. So if flexibility is required and you have room, go with the silicone wire. If you have less space and rigidity is not a factor, go with course wire stands.

Skin effect as I understand it is an AC phenomenon. It doesn't effect DC.

:D :bolt:
 
Other choices ; Superworm and Silverworm https://www.acerracing.com/Wire-74-1.html . Also Acerbraid , flat braided , silver plated copper wire for building battery packs.
 
Along with the point about skin effect being negligible for brushless motor drives, I don't know that rationale of needing fewer strands for higher current applications. The total cross-sectional area of all conductors is what counts. Welding cable carries very high current and it's finely stranded.

I suspect a cable made with many fine strands is more expensive to produce than one with fewer, thicker strands.

Sometimes the rigidity of low strand-count or even solid conductor cable is quite useful for bus wiring as once bent into position it tends to stay put, unlike flexible cable which can be like wrestling an angry python.
 
markz said:
home hardware 10 guage with a few course threads of wire

Bought some 10awg wire at H.D. today on the returns rack for 50% off, got 4m for $2cdn, its single conductor and course threads
H.D. is Home Depot? What you most likely buying is THHN

THHN Thermoplastic High Heat-resistant Nylon-coated. I know what you mean "It is stiffer and doesnt have a nice feel" THHN is intended for use in things that don't move. [buildings] For a electric bicycle or any vehicle. Try buying wire from a auto parts store. I like colors. Good auto part store will order what ever you want and have it in a few hours or the next day.

Hobby King 10 guage with lots of fine threads of wire. That's good for things that move a lot. Robot or test leads on a voltmeter.
 
HD and Autoparts store are an option when other options are not available, like at 10pm.

Found this and it talks about, just like you guys said
https://www.jalopyjournal.com/forum/threads/should-you-use-fine-stranded-wire.731195/
I have decided to call upon my knowledge and experience as a degreed and licensed electonics engineer....retired some 14 years now, but still in possession of a fair amount of my memory.

There have been many threads where someone asks a wiring question and gets advised to use wire with as many strands as possible because current flows only near the surface of the wire. While this is true for higher frequencies, it is not true for DC circuits. The phenomena is known as the skin effect and is a design consideration for radar and microwave applications.

I will spare you the math, but this is a rough representation of skin effect at DC, low frequency AC, and high frequency AC, the white area illustrates the part of the wire not used for conduction.......
I grabbed this graphic off the internet, and it is not exactly correct...AC Resistance is an incorrect term. In AC circuits, it is correctly referred to as Impedance, a beast affected by frequency, inductance, and capacitance.

skin effect ac.png

Bottom line..using high strand count standed wire in DC circuits will not improve conductivity. There is, however, an important reason to use stranded wire in DC automotive circuits....flexibility, a characteristic not only useful when routing wires, but also due to its ability to withstand vibrations.


Good for us, lots of vibes while riding ;)
 
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