Joint utility poles (was Re: Technical Demo turns political...) [Telecom]

'Typically' depends on where you live.

Here in Sydney the power is at the top, the phone line below, the first cable company (Telstra or Optus) below that, the second cable company (Optus or Telstra) below that. (I can almost touch some of them where they droop in the middle.) When there was a bush fire the whole lot went, poles and all, then they strung them back just the same :-(

Colin

If a joint pole includes power, there is almost invariably a _ground_ wire at the very top of things. I shouldn't need to explain why.

In the U.S. (at least, that's the geography of my professional knowledge, though the logic would seem to be applicable 'anywhere') power is also almost invariably (I don't know of even a single exception, but acknowledge that they may exist :) in the topmost position, for a couple of solid engineering reasons: 1) safety -- nobody has to go past the power to get to any other service. 2) pole-space efficiency -- power requires more physical separation from other services than anything else on the pole. By putting it 'on top' you only have one separation interval (below the power) of 'unusable' space.

After that, it tends to be -- in "descending" order -- a simple matter of the order in which pole space was rented.

AND, there's a third, 'practical', reason why power is on top -- it is usually the power utility who puts the poles in, in the first place. There is almost never a need for multiple services until power is there. About the only exception is some 'deep rural' areas that got telephone service before any other 'centrally distributed' service. One _could_ run, e.g., a farmhouse, without electricity -- gas appliances, gas lighting, gas heat, etc., all from an on-site supply tank.

It is *VERY* rare to see power piggy-backed onto phone company poles -- in part for the first two reasons mentioned above, and because power distribution requires considerably sturdier footing than just phone does. More separate strands (especially with multiple branches on a common feeder section) translates to greater wind/ice/snow loading which means increased lateral stresses as well as the added weight; then there is the weight of the transformer well.