[aberdeen5698]

Originally Posted by djh

Have you ever seen the usual 4-8-person crew working to replace a single wooden powerline post? It takes at least 2 days, and often they leave a stub of the old wooden post as extra support (presumably as the new one settles?) and they then have to come back at a later date and remove the old stubs. This whole process seems very very labour- and time-expensive.

It takes one day to swap the pole - I watched them do it behind my house a couple of years ago and shot a time-lapse video of the process. It's actually quite clever how they do it.

The video: http://www.youtube.com/watch?v=u0Knzw5a56M

I believe the pole in question was an original one for our street which would place it at circa 1949.

The reason they leave the stub pole there is because it carries not just the hydro power lines but also the Telus and Shaw phone and cable lines. They're not authorized to monkey around with those other companies' infrastructure. So the leave those lines attached to the old pole until the other companies come along and move them to the new one, then they gather up the old poles.

Now compare to a street lamppost, or the high-tension power cables that span remote parts of the country. Made from metal (I would assume modern ones are aluminum or perhaps stainless steel) - as a result they are very weather-protected. Once they're up they're up. The poles themselves need less maintenance (lamps themselves obviously need changing). And they tend to be much more resistant to extreme weather you don't usually see toppled lampposts in the city after major storms).

I've never seen toppled utility poles after a storm, either. Trees come down because the branches and leaves catch the wind, but that's not an issue with utility poles.

Also, you need to bear in mind that the 220V feeder lines that run down the laneways are fed from transformers connected to a high voltage line (50KVolts, I think?) that runs along the very tops of the poles. Using metal poles may pose some challenges in terms of dealing with those kinds of voltages in a fashion that doesn't compromise safety for the people at the bottom of the pole. Note in the video how much distance there is between the three wires that carry the 220V power and the high voltage line at the very top. It would be difficult to provide that isolation distance on a metal pole.

Ultimately I think the power and cable lines would be better-off underground, but every time a neighbourhood wooden pole needs replacing, it might be smart to go with metal over wood.

The people who run utilities all over the world aren't dummies. If they thought they could do it cheaper with metal poles I'm sure they wouldn't hesitate to use them.