"What wire size do you use for ESC, motor, LiPo batteries, signals...." I see this question all the time.
So here is some info that hopefully answer this question for you.
First of all, there is no "overkill" when it comes to the size of a wire, you can use thicker wires than you need.
A thicker wire means less resistance, and less resistance means less heat, better safety and higher efficiency.
However thicker wires are heavier, so for weight critical application such as building a quadcopter, we should properly choose the AWG of electrical wires to achieve a good balance between current rating and weight.
Mini Quad components normally comes with wires soldered: for example motors, ESC, batteries.... If you want to extend the wires, you can simply match original wire AWG on these components.
For example if your lipo came with 14AWG wires, you could use 14AWG wires for the XT60 pigtail.. And if motors were using 18AWG wires, but the ESC were using 20AWG, I would say it's best to match the larger wires, in this case, the 18AWG.
Note that some manufacturers would deliberately use thinner wires so the weight looks better on paper.
For signal and data wires, 26AWG to 30AWG should do nicely. They don't really conduct a lot of current so light weight thin wires should be okay.
It's hard to say what the current rating is for a specific wire size, because it can depend on the conductivity of the material, length of the wire and many other factors, but here is a simple chart that you might find useful - https://oscarliang.com/wire-awg-chart-quadcopter-rc/
Beware that the length of the wire also matters, as it increases the resistance in the wire as it gets longer. Therefore if you are using a long wire you should be using a thicker wires. But generally speaking on a mini quad you should keep any wire as short as you possibly can.
Finally Study on Ohm's law it should answer some of your questions
So here is some info that hopefully answer this question for you.
First of all, there is no "overkill" when it comes to the size of a wire, you can use thicker wires than you need.
A thicker wire means less resistance, and less resistance means less heat, better safety and higher efficiency.
However thicker wires are heavier, so for weight critical application such as building a quadcopter, we should properly choose the AWG of electrical wires to achieve a good balance between current rating and weight.
Mini Quad components normally comes with wires soldered: for example motors, ESC, batteries.... If you want to extend the wires, you can simply match original wire AWG on these components.
For example if your lipo came with 14AWG wires, you could use 14AWG wires for the XT60 pigtail.. And if motors were using 18AWG wires, but the ESC were using 20AWG, I would say it's best to match the larger wires, in this case, the 18AWG.
Note that some manufacturers would deliberately use thinner wires so the weight looks better on paper.
For signal and data wires, 26AWG to 30AWG should do nicely. They don't really conduct a lot of current so light weight thin wires should be okay.
It's hard to say what the current rating is for a specific wire size, because it can depend on the conductivity of the material, length of the wire and many other factors, but here is a simple chart that you might find useful - https://oscarliang.com/wire-awg-chart-quadcopter-rc/
Beware that the length of the wire also matters, as it increases the resistance in the wire as it gets longer. Therefore if you are using a long wire you should be using a thicker wires. But generally speaking on a mini quad you should keep any wire as short as you possibly can.
Finally Study on Ohm's law it should answer some of your questions