We have clearance lighting on out smoke stacks where I work. There is a
cable that runs inside a pipe to the light and another trolley cable to
guide the light down. As the light starts to be lowered it unplugs itself
the trolley cable keeps it from hitting the stack on the way down and guides
it back into the socket on the way up. It is all done with a hand crank
thankfully I have not been picked to change these lamps(a whole lot of
cranking). The lights along the interstate as similar but I do not think
they use a trolley cable and rather use the pole itself. I have seen this
method used inside buildings with very high ceilings.
> >several pointed out you cannot climb the large non metal poles for
> >lights etc around the interstates.
> Next time you drive past one notice the access panel at chest height near
> the ground. I think there's a winch in there where the crew lowers the
> light head to ground level to perform maintenance.
> I would not know this except I saw a crew changing bulbs once - the
> equipment head which usually lives at the top was down about 5 feet off
> ground. Ingenious. Sort of like an "internal Hazer." It must also have
> lot of extra AC cable in there because what comes down must go up, or
> whatever. Maybe they disconnect the electricity before they lower it, and
> the wire end goes up, then when the head goes back up the wire comes back
> down. Then they plug it in again and test their work.
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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