[LINK] Four Corners NBN

[David Boxall]

On 12/04/2011 10:05 AM, Jan Whitaker wrote:
> At 09:32 AM 12/04/2011, Marghanita da Cruz wrote:
>> I doubt there is any plan to put the cables to the
>> home underground as they recently upgraded them to Aluminium
>> "to make them more robust" against the trees.
>
> Probably depends where you are in the country. We are total
> underground power and all other lines. As a result, I seldom have a
> power outage, I think 2 or 3 in>12 years.
>
> What does 'against the trees' mean?
> ...
I'm no expert but, where I am in rural Australia, all of the power lines 
are aluminium. Distance between poles is far greater than in urban 
areas. To withstand the necessarily greater tension, I'm told, the lines 
have a steel core.

Those lines are apparently more elastic than copper; they'll stretch, 
then snap back, where copper stays stretched or breaks. I've seen trees 
fall across power lines, bringing them to the ground without breaking. 
The sight of them sparking and crackling, as the wires sear into the 
timber, is quite spectacular. I've felt a tingle through my shoes, 
standing more than ten metres from downed lines; under different 
circumstances, getting that close could be fatal (I'm told). Cut the 
power, remove the fallen tree, and the lines spring back so power can be 
restored; much cheaper. Bear in mind that I'm not referring to your 
urban 240 volt line.

Underground is generally accepted as more reliable and cheaper, both 
financially in the long term and for public liability costs. The hazards 
and vulnerabilities of underground infrastructure are minuscule compared 
to overhead.

-- 
David Boxall                    |  When a distinguished but elderly
                                |  scientist states that something is
http://david.boxall.id.au       |  possible, he is almost certainly
                                |  right. When he states that
                                |  something is impossible, he is
                                |  very probably wrong.
                                                  --Arthur C. Clarke