Pushed hard so less is lost
Why Are Power Lines So High Up?
Electricity leaves a power station at a pressure that would kill you instantly, and arrives at your house gentle enough for a lamp.
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Step 1 of 5
Wire wastes electricity as heat.
Electrons bump into the atoms in a wire and every bump makes heat. Over hundreds of kilometres those bumps would waste most of what the station made.
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Step 2 of 5
Pushing harder means fewer electrons need to move.
The same amount of power can be delivered as a gentle push on many electrons or a huge push on few. Fewer electrons moving means fewer bumps — so the waste falls dramatically.
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Step 3 of 5
Transformers change the push.
Two coils sharing an iron core: electricity in one makes a changing magnetism that pushes the other. Different numbers of turns give a different push out — up at the station, down at your street.
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Step 4 of 5
Height and spacing are the safety.
At that pressure electricity can jump metres through the air. The pylons hold the wires far from the ground, far apart from each other, and hanging from long glass or ceramic strings.
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Step 5 of 5
The grid is one enormous shared circuit.
Every station and every house on a country's grid is wired together. Demand anywhere is felt by generators everywhere, and they are all kept spinning in perfect step with one another.
Birds sit safely on a line because both feet are at the same pressure. Nothing pushes through them, so nothing flows.
The short version
Power lines run at enormous voltage because that wastes far less over distance, and transformers step it down before it reaches you.
Try it yourself
Look for the grey drum on a nearby pole or the fenced box on your street. That is the transformer that makes your sockets safe.
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