[telkanuru]

To the original topic, I believe it comes down to safety factor. Safety factor is a simple calculation- the max voltage/force/whatever an item can withstand theoretically divided by the max it's supposed to take. So a wire capable of carrying 40A on a 20A breaker would have a SF of 2. A SF of 2 is recommended on devices that do not have the possibility of endangering a human life, SF of 3+ otherwise. As for connecting larger wires to smaller, I guess they can't do much about their suppliers...