Why is electricity sent across the country at very high voltage instead of the 230 V we use at home?
Power lost in the wires is I²R.
Power lost in the wires is I²R. Transmitting the same power P = VI at a much higher voltage means a much smaller current, and since the loss goes as the square of the current, high-voltage transmission slashes heating losses. Transformers step the voltage up for the long journey and back down for safe home use — and transformers only work with AC, which is a big reason we use AC.
Key point
High V → low I → far less I²R loss over long distances.
Common mistake
thinking high voltage itself wastes more energy in the wires.
Memory tip
losses scale with current squared, so cut the current by raising the voltage.
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