I thought about that, and then decided as a statement of fact it was bollocks.
Consider a set of telephone wires all starred from a single point where they are all shorted together. Telephones are oin te end of each pair.
One of the wires goes through a transformer that is designed to induce current in it. The telephone on that wire and that wire alone will see 'hum'.
Telephone pairs are balanced and should be relatively immune to picking up hum.
Unlike the bodge that was the BT three wire house wiring. That is excellent at picking up induced signals.
Except that mine are wired as a spur. I am quite surprised the hum does not go back the way to number 2.
Only for new installations
Historically, when the suppliers were all nationalised there were occasions where telephone cables were added onto electric poles, usually done in the era when a lot fewer people had phones so installing new poles just for one new subscriber wouldn't be cost effective.
And not smoking.
That's early H&S - you wouldn't want him to risk catching the tie and hanging himself!
What happens with TN-S if you are fed from a pole? Do you get a separate earth conductor, or are they all TN-C-S or TT?
One possibility in the OP's setup is it's TN-S because it goes to a buried cable somewhere, and the earth is to earth the cable sheath.
Theo
The introduction of fibre has caused some scenarios where the present distribution companies have created a fuss because they say it is new technology not covered by the long standing agreements that allowed the Post Office and its successors to affix a copper phone line on suitable power poles so Openreach if it wants to run a fibre has to make its own arrangements.
GH
Philosopher, starting with a false assumption is always a bad start, but star, daisy-chain or hybrid. Would you describe the path(s) of the induced currents for no handsets lifted and for each handset in turn lifted?
Scott, have you tried swapping around the handsets? Just a bit more evidence.
PA
There are loads of telephone cables sharing electricity poles near me
https://www.google.com/maps/@51.255834,-1.0164282,3a,42.2y,57.57h,110.54t/data=!3m6!1e1!3m4!1sjFgOaCG_XpbaFz7chgQYdg!2e0!7i16384!8i8192 Our own telephone cable also comes via an electricity pole too, though it starts life on a BT pole the other side of the road.
If/when that gets replaced by FTTP, are you saying it'll have to run either directly from BT's own pole (and not involve the electricity pole)?
Not the case here when FTTP was put in. They used the same poles for the fibre as did the copper and the electricity. Pole sharing is not unusual, certainly in rural areas.
Less needed with fibre. It's not a good conductor of eletricity
Indeed it's not, but I think the concern here is BT Openreach personnel are !
No, the X spacers for the four conductors on each phase of supergrid lines give the overall conductor an electric field distribution more like a larger diameter conductor, reducing the corona losses. I guess they also reduce the conductor temperature at a given current from the level if all the aluminium conductor was wrapped around a single steel (load carrying) core.
See my resp to TNP below
As a data point, our FTTP cable was run from the same pole outside our house that carries our electricity supply and old copper telephone drop wire. And those of several neighbours. So perhaps the rules about fibre cables only applies to long runs rather than final connections, if it applies to all electricity distributors.
And don't the fibre cables include a steel rope to take the tension?
Is there a steel catenary wire inside that hollow tubing used to support overhead fibre ?.
what a bodge
If its 'always been done that way' my guess is it will still be done that way!
yes. and a copper pair, too.
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