Der!!! I *am* misremembering it. Neutral should be virtually at earth potential (*), not at one of the phase potentials. Of *course* there has to be a separate neutral line to make this happen ;-)
(*) I believe in some installations, neutral is actually bonded to earth at the premises.
Jump a couple of meters down the road and then you see this
Do we actually have 'utility poles' in the UK? They are standard practice in the USA, where they carry power, phone, cable TV etc (but, as far as I know, not gas and water!), and I've seen them in Belgium - but they must be pretty rare in the UK.
insulating spacers to stop the phases getting too close in the wind?
That sounds like a recipe for disaster to me. Hum induced voltages and damage putting dangerous voltages up a phone line. Brian
Many moons ago down a country lane in Cornwall, I was young kid and we all were stopped in our tracks by a team with a cherry picker doing something on the wooden pole at the side of the road. I think my dad got out to stretch his legs while we waited, and asked one of the blokes there why there were so many wires and apparently all bundled together every so often. They told him one of them was a steel wire to help stop the others stretching and did nothing else. Brian
yes.
Climbing a power pole requires a hugely different safety regime from skinning up a telephone pole.
it aint no silly 110v either. its 230v.,
Yep. I see it when I look further down.
And a customer sent me this last week
But those "X" spacers which the commentator says are to stop them shorting the system, are on wires of the same phase!
before the days of H&S. No hard hats, no harnesses, even the club hammer had to safety chain ----- mmmm
Our electricity and telephone come from the same pole outside our house. Openreach technicians say it is undesirable, but there is really nowhere else to put a pole without the mains and telephone drop wires interfering with each other. I've never seen a telephone cable on an 11kV pole though!
Not at all. Induction makes little difference to our, notionally balanced, telephone network and the anchor points are well below the power cabling. There are several examples of this practice in the Google Map views the OP offered us.
It is instructive to connect a phone line to a spectrum analyser and oscilloscope. When looking at either wire there is masses of pickup - predominantly of the Medium Wave - but some 50Hz, too. If you then couple both lines via a balun to the spectrum analyser/oscilloscope, you - thankfully - see way, way, way less unwanted stuff.
PA
You could try wiring this extension with proper twisted pair instead of ordinary telephone internal wiring which isn't (twisted, that is).
This one has a bloke in a suit going up the pylon
If all of your extensions are simply connected across the incoming pair, then induced hum won't just affect one extension.
PA
It seems impossible to find an official GPO/BT/Openreach spec for CW1308 internal phone cable, but various manufacturers specify theat they use different lay-lengths for the individual twisted pairs, e.g.
The man's got no bloody tie on! Shoddy dress leads to shoddy work.
Is that 11kV between phases?
they are to stop wires *chafing*,when on the same phase.
Have something to add? Share your thoughts — no account required.
Ask the community — no account required