Hi im "new" here. Uh so the speed of electricity in copper is about 95-97% of the speed of light. Now to clarify. That is the speed it uses (say DC) from one place to another. And the reason for the loses in speed is due to the electrons having mass. So when one bumps the other the other takes some time to get moving. Is this correct? So.. those five percents it loses in speed.. thats energy, does it go over to heat? hence the slower speed in lesser leaders -> more heat generated. I see no other explanation.