Philosophy behind wiring rule C6...

[Mike Betts]

CBP:

The amount of current a wire can take is a function of the diameter (AWG) and the type/thickness of insulation. The type of insulation determines the temperature at which the wire will fail. The thickness (among other factors) determines the voltage at which the wire will suffer a dielectric breakdown and arc over.

The next thing to understand is that the wire generates heat when a current passes though it. With a "perfect" insulating jacket, the heat would never escape and the temperature would rise to infinity. All things being equal, the thicker the insulating jacket, the higher the temperature of the conductor will become before thermal equilibrium is established.

Now... Most all wire commonly available is either 300V or 600V wire. This includes the 10 AWG wire FIRST provides. The insulation is thick and heat builds up rapidly. Whereas the voltage rating of the wire on the motors is much less (it is custom built for the motor manufacturer) and less heat is built up.

With special, low voltage, Teflon (high temperature) wire, the motor leads could be made as small as 18 AWG or so (but this is expensive wire...).

Bottom line: FIRST has tried to be conservative and safe and still allow you to use readily available off the shelf wire. Please do not try and "second guess" without doing the engineering calculations which are verrrry messy (been there and done that).

Use the 10 AWG wire and move on to other problems you might have...

Mike Betts
Bobcat Robotics

Postscript to Mr. Dwarf:

I'm not sure what you have done but be sure to have an electrical engineer check it out. If you don't have an EE on your team, seek help from another team at your regional... I'm serious... It sounds like you have heat shrink tubing holding a 10 AWG wire on the motor terminal and that sure fire is a recipe for a failure.