Have you ever seen real word results under normal use on an e-board where 10AWG wire got so hot it could melt insulation ? I don’t agree on high strand having more copper for the same gauge but I don’t want to hijack @disastorm 's thread so I’ll leave it at that.
i’ve been using Super Worm high strand silicone insulated wire which is pretty common in the RC world. It comes in multiple gauges and works really well for everything in the box. I only use 10 awg on battery wiring and typically it seems like motors are coming with 12awg phase wiring, so i’ll use that when i need to make phase leads.
The only time i’ve ever seen the insulation melt or burn is in two edge cases: 1) when i screw up and throw sparks. But when that happens, entire bullet connectors can disintegrate and throw slag everywhere. 2) when i lay the soldering iron tip directly on the insulation, but even then it just sort of gets soft, it doesn’t discolor and do that margarine separation thing that automotive wire does.
In all three of the boards i’ve prototyped with inlaid wiring i’ve used 10awg stranded wiring with non-silicone insulation, basically automotive wire. The insulation on that wire does separate and get gross and oily with heat, so when filling the back of the bullets with solder i have to be careful. I use that wire in that particular case because its not springy and holds its shape when bent.
long story short: super worm and other high strand count silicone insulated wire is the shit and its the best wire for inside the box for many reasons.
For those of you who want to count the strands here (wire at the bottom) is the wire that came on the last batch of VESC, its 12AWG high strand count copper wire with polyurethane insulation rated to around 100C. The one at the top is “12AWG - high strand count - tinned copper wire - with silicone rubber insulation”
If you have silicone rubber insulation the wire can heat to 200C without melting the insulation… If you dont have it your wire insulation will melt at lower tempratures.
If your wire temprature reaches 200C you have other issues that need to be addressed, such as why your system is pulling such a huge amount of amps.
Found this on Quora, too late for me to type it out.
Either is fine. While it is true that at very high frequencies, solid conductor wire shows increased impedance due to eddy current forcing the current to the outside, aka the skin effect, that is not the case at 60Hz and common wire sizes. (Note: a useful approximation for the wire diameter where the resistance increases by 10% is Dw = 200/sqrt(f), with f in Hz and Dw in mm. So for 60 Hz, Dw is 25.8, or just over an inch.)
The reason that we use stranded versus solid wire in our day to day lives is that solid wire is cheaper, but does not put up with the constant flexing of power cords. So, we have solid core wire in our walls where it does not need to move, but cost matters, and stranded wire in our power cords where a solid wire would quickly work harden, embrittle and break.
Now, as to why the solid wire would work harden, embrittle and break, you need to understand that the strand diameter relative to the bend radius is what determines how much strain is imparted into the wire. Solid wires have large strand diameters and see lots of strain. Stranded wires have strands with small diameters and see much less.
One last thing, the above statement about skin effect being of no consequence until relative high frequencies speaks to the actual sinusoidal components. So if you have a square wave (or close to it) you would see quite a bit of impact on your edges if you used thick solid conductor wire. Similarly, if the wire is in a magnetic field, say in a motor, eddy currents come into play at much lower frequencies.
I have learned long ago, when working with electricity it is best to stay within the specs of the materials and component used.
I design for the worst possible scenario, 6s single motor pulling close to 80+ amps. The specs on 10 awg high strand silicone wire barely meet this demand. If you were to run conventional multi-strand 12 awg wire with a nylon insulator it would quickly heat up and possibly melt the insulator.
Someone new to the sport will more, often than not, come to the plate with a 6s lipo and the capability to pull 80 amps becomes quite an easy task. It is irresponsible to use anything not built for the worst case scenario.
Thanks for this @chaka; we had a thread a few months ago abut wire guage and I had concluded that for my 8s system with a single motor (max 70A), 12AWG silicone wire was sufficient. I’ve had no troubles with this set up so far. Do you think the that conclusion was correct?
Are the max motor amp ratings provided by manufacturers reliable, or are those figures exceeded in real-world use?
I based that on the image below that @lowGuido shared.
In my honest opinion good 12 awg silicone wire will “get you by” but it is going to get hot frequently. DrBass did an actual real world test showing the actual temp measured through the insulation. You can imagine the conductor had a temp much greater than this.
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while I agree that bigger is most certainly better when it comes to wire gauge and current flow. well it is always better. heck just go as big as you can!
although sometimes we have to be a bit realistic with space and what not on our boards. its also important to remember that these are skateboards and not RC cars. I have never pulled anywhere near as much current on my skateboards as I would on my RC car. my RC cars are regularly HOT to the touch. in fact I have actually burned my finger picking up my car before. my skateboard has never been that hot, ever.
to put this in some kind of scientific perspective for those who prefer that kind of thing.
I ride my skateboard for close an hour and I get about 15km out of the battery so my average speed is 15km/h my battery is 5000 mAh, so you could say over my 15km hour long trip I have average current Draw of 5 Amps
wait? what? average of 5 Amps? that doesn’t sound like very much? but facts are facts on my average skate on any average day, my average current draw is 5 amps. yeah sure i’ll pull some 40Amps up a hill for a short time or something but these bursts are only short. my average load is well within the specs of a good quality 12AWG cable.
UNLESS you are doing massive hill climbs for extended periods…
everyone’s situation will be slightly different, but 100A? I’m never gonna see it. you guys have all the data of your own builds, you can do the simple maths and work out for yourselves if its worth the extra guage or not.
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trying to cram 10awg silicone wire into a low profile box with all the other stuff and having to route it all crazy because you have multiple ESCs and what not is already a challenge. 8awg would be a total troll, so i stick with 10awg.
since i’ve been testing this 10S build i’ve only found coolness. Cool motors, cool wires, cool ESCs, cool box. immediatley after a sprint i have warm (but not remotely hot) motors, cool wires, cool ESCs and a cool box and a set of warm (again, not remotely hot) belts.
Hot? The only time i’ve seen hot is when my pulleys on my 6S worked their way into a rub with the older open source mounts i have on there and my 5060 270s were heating up as a result. That was the result of bad belt alignments and not using proper clips/keyways/notches while attempting to top out.
What do you guys suggest for a good flat cable that will hide well under grip tape?
for power? or phase leads?
For power. I want to do my own kind of boosted clone without carving the deck to hide cables 
Something like this might work.
Is anyone else familiar with guaging requirments for the kinds of loads we would be putting on braided copper flat wire?
I’ve often thought of doing something like this.
The net copper cross section is important but it’s not stated in the ebay item description. But let’s say this braid is 1mm thick and 15mm wide, and contains 50% copper (estimate, the rest ia air between the individual strands), you have 15 x 1 x 50% = 7.5 square mm copper, which is a bit less than AWG 8 but more than AWG 10.
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I know under ceramic tiles we used to use flat copper wire when connecting floor heating systems, kind of like the old window security tape but heavier gauge. Wonder if that could also heat the deck for those chilly morning commutes??? LOL
Interesting discussion, but I have a point to add here. I believe current (amps) only flows on the surface of a copper wire, hence high strand wire (more surface area) could deliver better current compared to same thickness of a single copper wire.
You are referring to the skin effect, that happens at high frequency, not high current. Stranded and braided wires offer a mechanical advantage where the wire can be move around more than a single conductor with the same gauge
Ohh well yes you’re right. My mistake 
I’d like to point out that space cells apparently have 16awg mains. 16 GAUGE MAINS.
which makes my 10 gauge mains policy pretty pointless as far as I can tell. I may as well just run 16 awg all the way up to the VESC.
when i build my own packs they will have 10 gauge super worm mains. They’ll also be 12S, but that’s another topic for later.
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I’ve totally agree with 10 gauge by far is the most suitable wire I’ve ever used. It’s not as rigid as 8 awg but does feel more sturdy than 8 awg. Lipo packs with 20 - 30c discharge uses this 10 awg - 12 awg wire, so it’s also good reason to stick with it. 8 awg wire also doesn’t fit into XT60, so it requires more expensive XT90 plugs. And again all of these wire sizes in the circuit does get affected by the weakest / thinnest cable, so thats the reason I also stick with all 10 awg.
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