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Shocking spelling lets you down.Neutral to avoid the problem. I have come across hundreds of examples in my working life.
Discuss Earth Rod - Advice please! in the UK Electrical Forum area at ElectriciansForums.net
Shocking spelling lets you down.Neutral to avoid the problem. I have come across hundreds of examples in my working life.
The armouring is tinned steel. The tinning was often poor, the plastic outer gets damaged, water gets in and the steel rusts through. All the RECs/DNOs know this is a significant problem with ealry XPLE 3 core three phase U/G cables. Modern ones are better, but many now use 4-core cables with a separate Neutral to avoid the problem. I have come across hundreds of examples in my workig life.
Im struggling to find any reference to this cable at the moment, it doesn't appear in any of ukpn's documents on legacy equipment or jointing manuals as far a separate I can see.
Does this cable have a unique name or identifying acronym I can search for?
Also do you have any answer to my other questions?
XPLE stands for Cross-Linked Polyethylene which is now commonly used for SWA cables.
PVC SWA vs XPLE SWA? - http://www.electriciansforums.co.uk/threads/pvc-swa-vs-xple-swa.53841/
Early versions were not very reliable as they were susceptible to mechanical damage and water got in to the armouring. The steel was not stainless nor adequately plated and the water causes it to rust through, removing both the Neutral and Earth connections as the 3-core cable does not have a separate Neutral conductor.
The higher harmonic frequencies (not just 100 and 150 Hz) become a higher % of the total current when the three-phase currents are unbalanced and there is no Neutral. In fact the current usually becomes very noisey with lots of semi-random noise as well. That is also partly due to the large number of switched-mode power supplies now used in most consumer equipment instead of transformers.
p.s. I like your photo - I have been a "landy" man since 1971...
I am well aware of what XLPE stands for (not XPLE) and it's applications in modern cables. What I'm asking for is some sort of reference to the actual type of cable you are describing as I can't find any reference to it, or the problems, in any of the documents I have from a DNO regarding problems with legacy equipment or jointing instructions for legacy cables.
Harmonics in the neutral conductor are a problem which is well known about yes, particularly third order harmonics which don't cancel out in the neutral conductor. SMPS and other electronics are a cause of this.
But you said that PME is a cause of 100 and 150Hz magnetic fields, the harmonics you are describing are not unique to PME and don't explain these elevated magnetic fields you describe. How is PME causing this?
And my third question was regarding the timeline. You stated that PME was done in the 70's and 80's to failures of early 3core XLPE cables, yet multiple earthing has been detailed in regulations and reference books since the 50's. Also if it was 3core cable then it would have been installed as PME from the outset and so to say that PME had been later applied to the failing cables just doesn't make sense.
I am open minded on the subject and and happy to be proved wrong in my current understanding and belief, but I will do my own research to find before changing my mind. At the moment there are too many apparent holes in your statements.
I have no problem with the idea that magnetic fields could have an effect on living tissue and organisms, but I have yet to see any believable way that this could extend to causing specific cancers in young humans.
I can't provide any back up info right now Dave but I'd say the problematic network cabling would have been far more likely to be aluminium that caused problems in the 70s and 80s ?
It would be a rather silly arrangement, not one I've ever seen or heard about.I didn't think steel had ever been used for a live conductor in underground LV mains.
they won't go till all the polar bears have gone south.Isn't planet earth one dirty great big magnet? Funnily enough they reckon it's in a state of flux at the moment and it's about to swap poles!
What I like to know is... if the earth flips poles does that mean all the penguins will have to swim north?
I live and work in that areaI am slightly surprised that near Gloucester city centre the electricity distribution network is not PME (T-N-C-S) with the Earth connection being supplied with the network supply to the house. I wonder if there was a problem with that and the Earth Rod was a dodgy relatively quick fix to lower Ze rather than getting the DNO in to sort their problem. Check if your neighbours all have Earth Rods. If you need one, they will also need one. If they don't have them, then I would ask for a second opinion. You could check with Western Power Distribution on 0845 601 5972 and ask them if your house should need a separate earth rod. If there is a PME system then you should normally not also have an Earth rod as it can lead to stray currents in the network and elevated magnetic fields in your house.
Isn't planet earth one dirty great big magnet? Funnily enough they reckon it's in a state of flux at the moment and it's about to swap poles!
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Reply to Earth Rod - Advice please! in the UK Electrical Forum area at ElectriciansForums.net
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