Re: Power Line Insulators

[Wolfgang Rueckner <rueckner@FAS.HARVARD.EDU>]

The shape of the ceramic insulators maximizes the distance (along the
surface) from one end of the insulator to the other.  That increases the
maximum voltage that the insulator can withstand.  Insulator breakdown (due
to excessive voltage) occurs on the surface first -- leakage paths will
form on the surface and thus the path is made as long as possible.
Wolfgang

> I've been watching new power poles go up around our campus and it
> occurred to me that the insulators that hold the wires always have the
> same basic shape:  what appears to be ceramic "disks" stacked together.
> I've tried to think through why this shape is important, but so far I've
> come up empty.  Does it perhaps have to do with moisture shedding?  An
> increased surface area would get rid of heat more efficiently, but these
> insulators shouldn't get that hot anyway, right?
>
> I'm likely missing something really simple, but I'd appreciate it if
> anyone out there knows the answer, please give me a clue.
>
> Thanks.
>
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