As I said in my post you are referring to, heating rate for a given load (resistance) is proportional to the square of the current times the resistance:
Heating rate = current x current x resistance
But Ohm's law relates the resistance as the ratio of voltage and current:
voltage = current x resistance
So the heating rate (by the virtue of Ohm's law) becomes the product of the voltage and the current:
Heating rate = current x voltage
which is what we understand by the 'power' flowing through the circuit.
If you read carefully, you will find both of us are saying exactly the same thing.
BTW, the reason an overload beyond 20A may not be tripping the breaker is because a factor of safety (1.5) is built-in. Thus I think what is labeled as a 20A breaker, is actually a 30A breaker.
No, it's actually a 20 amp breaker. See chart below for how breakers work. A 30 amp breaker will have higher trip currents for the same time factor than a 20 amp. It is not a "safety factor".
If "google" stranded wire vs solid core wire you will find out that at 60hrts there is virtually no difference between stranded and solid core wire regarding resistance. The skin effect comes into play at much higher frequencies.
The main reason for using stranded wire is that in larger sizer it is more flexible.
Yes, and it's hard to convince people of this. They read it somewhere, and didn't notice or dont remember the part frequency plays in skin effect.
No, we're not. Your inclusion of ohms law into what we are talking about is dead wrong. Voltage has no significant affect on the heating of a conductor.
Edit: I think I see what you are trying to do, but it doesn't work the way you are thinking. If you want to substitute voltage into the equation for heating of the conductor instead of current x resistance, you have to use the voltage drop across the conductor at load, not the circuit voltage.
True, you can't use current at applied voltage to figure heat loss. Most of the power consumed is at the load, only a small portion is lost in heating the conductors. The only time when the heat in the conductor becomes a factor is when the wire is too small for the load current, and the heat is enough to damage the conductor.
When a conductor becomes appreciably warm to the touch, not only is it too small, but it is causing more heat buildup in any motor it's supplying. Not a factor in resistive loads, just a loss of efficiency.