Why don’t birds get electrocuted while perching on power lines?

It's all in the difference between voltage and voltage difference.

Asked by: Ahmed Hussain, London

It’s not voltages per se that kill, but voltage differences, which are needed for electricity to flow. If a bird lands on a single power line at, say 35,000 volts, the lack of a voltage difference keeps it safe. If it extends its wings and touches another power line at a different voltage, though, it will be electrocuted. That’s why electricity companies put plenty of space between cables.

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