8 AWG wire?

[ElectricThunder]

Anybody ever try using 8 AWG wire on an ESC or battery yet? I ask because my friend just found some in his room, so he gave it to me since he's not going to use it. It's high strand count too, so it's nice and flexible.:D

Just curious; I'm not running anything ridiculously high voltage or over powered, so this is more of a theoretical "what could I use it for if I so desired" type of deal.

[Smib]

While most likely completely unnecessary, it can only help in terms of lowering resistance, although it might add a couple ounces to your weight.

[ElectricThunder]

Well, I'd run this in a Rustler, which is already a tank. On the plus side, I just took the plunge for lipo...so it's all good in the weight department.

[schenck77]

never used 8 awg. I do have 10 awg on my brushless 8th scales though.

[Demon-TC3]

Well, 10 Awg can be used for jump starting a car, so i can only imagine what sort of current 8 can handle! frankly, i dont think you need more than 10...
average 12Awg can handle 100A easily so 10 must be in the 130 area...not many esc's that will handle that much :P

Still, cant hurt,
Good luck
Demon

[ElectricThunder]

Yeah, good point. I just figured I'd get some ideas since I picked some up for free. I'm sure I'll do something with it eventually....:D

[howielong]

Arg you guys are making me break out my NEC Code book here. :)

Table 310.17 States for Wire type THWN which I think you have for single insulated conductors rated up to 2000 volts.

14AWG wire is good for 30amps at 30Degree C.
12AWG wire is good for 35amps at 30Degree C.
10AWG wire is good for 50amps at 30Degree C.
8AWG wire is good for 70amps at 30Degree C.


But really it is unnecessary to use anything over 12AWG in a RC. I have yet to get get really even 14AWG wire hot enough to desolder it off a terminal. Plus how many ESC have a large enough area to solder on 12AWG wire let alone 8AWG wire with out cutting part of the wire or stands away to get it to fit.

[Demon-TC3]

yea, many esc's struggle with 12AWG wire - Mind you, those ratings do seem allot lower than what i thought, as far as i remember, 12 was safe to use up to 80 or so Amps...

[howielong]

yea, many esc's struggle with 12AWG wire - Mind you, those ratings do seem allot lower than what i thought, as far as i remember, 12 was safe to use up to 80 or so Amps...

Do you want to see Table 310.17? I do know what I'm talking about. So does the NEC which is the National Electric Code. Plus wire is UL listed and test at its maximum amperage. Most wire nowadays could hold more amps but only for a short amount of time before they start to deteriorate and fail. Thats why you use certain wire for certain applications instead of using 14AWG wire for a kitchen stove when you should use 8AWG or 10AWG wire.

[Demon-TC3]

No offence implied - surely the material of the wire actually plays a huge role as well as the strang Count? i personally dont really know much about wire, neither do i want to act like i do - all i know is, the thicker the wire, the less resistance (well, usually).

but, when i was selecting wire for my brushless conversion, im sure i read that 14 Awg is for up to 70A opperation: http://www.unitedhobbies.com/UNITEDHOBBIES/store/uh_viewItem.asp?idProduct=5157

Still, you seem to know more about it, mind you, i dont think it would really matter for rc what you use, be it 14 guage or 12 guage.

[MikeInCtown]

What you guys who are quoting the NEC don't realize is that changes in voltages affect how much amperage the wire can carry. I can't remember the formula, but someone would be able to do a search easy enough.

Anyway, 8 guage for a home is quoted in the NEC as THHN in most cases or possibly underground rated or maybe even free air rated.

The wire that the poster most likely has is rated for 12v automobile systems and is probably rated for 12v at a much higher amperage than what the NEC has quoted for THHN wire.

In any event, 8 ga wire in an RC car is probably complete overkill in almost all circumstances.

[pleaseletmeon34]

I saw this thread earlier... and past it by.

I've seen 80amps on 12 wire... insulation gone... glowing (on a DC control)

The gauge of the wire determines the ampacity. The insulation determines the voltage.

Even though the NEC lists it at 35amps, you're still only allowed to fuse it at 20 amps. Then you're only allowed to load the fuse/breaker to 80%.

So in your home... 16 amps is all you can "legally" put on 12awg.


I have some 535mcm locomotive cable if you think that will help. :)

[GSMnow]

The NEC ratings are for constant use in a confined space with other wires. You put 9 12 awg wires in a 3/4 inch conduit and pull 20 amps on all of them and that pipe gets HOT!!! Hang those #12 wires in mid air, and they run very cool at 30+ amps. Not put those #12's on a 60 amp breaker and watch the smoke. I watched it happen on a construction site. Ever see 100 feet of #12 wire glow bright red as the insullation all burns off? The 60 amp breaker never tripped, the wires finally burned through.

The high strand count and silicone insulation does increase heat handling capacity so it will take a bit more current before failing, but probably just 40 amps or so constant on a #12. My Mamba Max powered truck runs over 12 minutes on 4000 mah. 12 min. is 1/5 of an hour, so 5 x 4 amp hour is 20 amps AVERAGE current for the 12 minutes. That is what counts and is why #12 works just fine. Even if I killed it in 6 minues it would be just 40 amps.

Sure, #8 wire could help out with lower resistance, but I doubt you would even see the performance difference, especially with the added weight. A #10 awg wire has 1 ohm for 1000 feet. Or if you use 2 feet of wire total (way more than I have in my truck), you only have .002 ohms. Going up to #14 would increase that to .008 ohms. #12 is between them. #8 would be about .0012 ohms. Sure you might measure a difference, but I doubt you would feel it. #14 might get hot enough to degrade over time though.

The NEC codes are for life safety, so they leave room for error in everything. An 80 story office building burning down due to a wire over heating would be very bad. An RC car not finishing a heat because a connector burned, not such a big deal.

[Demon-TC3]

hehe i just figured something - the reason 12 Awg is rated at such a low current is because you use such great lengths... and since R=PL/A then using 12 guage with a length of about half a foot, the resistance would be tiny meaning you can pump 100A through it with ease!

SO...we are all correct :D since in rc cars you dont use 100 foot of 12Awg wire you will be fine.