Subject: how in physic terms do u describe overloading of a circiut

i have a steel wool shaped in a circle with ends. i attach two aligator 
clips to both ends of the steel wool, and the other sides of the clips 
attached to an AC-generator. i let out 2V to the steel wool for five 
seconds and it smokes,when however i let out 6V for five seconds the wool 
starts to burn, then i let out 12V for five seconds aswell and it fully 
lights up. can u explain in physics terms how was the smoke born, and then 
how the fire was born. something maybe to do with electrons not getting 
through the wool, it all maybe building energy in the wool. thank u 

Re: how in physic terms do u describe overloading of a circiut