Why can’t they just make the insulation thicker on overhead power lines ?
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Mains distribution lines are at such a high voltage and current capacity that insulation would be extremely heavy and thus expensive/impractical.
Low voltage extension cables are safe with a thin plastic jacket.
overhead powerlines aren’t insulated. The insulation would break down due to exposure to heat and UV light. The excess weight would also put more stress on them; high tension lines carry tens of thousands of volts and the insulation would have to be prohibitively thick. People getting electrocuted by them simply isn’t a problem. Your money is better spent elsewhere that’s actually a problem.
Firstly you can get electrocuted on 240V. Don’t play with it. It’s dangerous.
Overhead lines typically aren’t insulated as that adds to cost, weight and poorer performance. Air is a good insulator, it’s easier to just space things appropriately. They’re built so that noone will accidentally come in to contact with them: you’d need to go out of your way to ignore safety barriers/climb a pole etc.
Obviously mistakes/negligence do happen. But it’s pretty rare, and in those cases it’s unclear if insulation would even help anyway.
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Overhead power lines have yards of insulation, that’s why they are up high this much. The insulation is clear and cut through very easily, it’s called air. Replacing that air with plastic or rubber would make those cables prohibitively heavy.
LPT: don’t touch overhead cables.
In addition to what others have said: insulating very high voltage is ridiculously hard. This voltage tends to break any insulator, and weather, like rain, Sun with UV, winds, temperature changes, etc – all it degrades insulation pretty quickly. With 25kV it only takes tiny crack to make a spark which would evaporate insulator and expand in milliseconds. So you’d have to change thousands of tons of insulation every month or so, which isn’t viable option. There’s underground powerlines for that – they don’t exposed to such harsh condition and at such depth temperatures are almost perfectly stable, so there insulation is an option, but still, it has to be repaired every so often, because, again, it’s really hard to keep such high voltage under control, and any crack in insulation that would allow arcing would expand rapidly and destroy the cable.
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