Electrified metal is metal that has been touched by electricity or acid. Electrified metal is the basis for most power-requiring actions in the game, including the usage of heater, cooler, note, and other things. The electrified metal must be touching the object to power it. The electric current speads through the metal by physical contact. If electrified metal and normal metal are touching, the electricity will eventually spread to the normal metal. If the horizontal tip of the metal has a radius of 0, it will leak electricity. Electricity in the sandbox follows a rule called wireworld; it is a type of cellular automaton. With it you can make lots of complex logical circuits. Learn more about it here.