eli5 why do people get electrocuted by live overhead power lines but not 240v extension cables ?


Why can’t they just make the insulation thicker on overhead power lines ?

In: 1

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.


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.