Lots of faults due to incorrect and poor tie pair terminations. Probably the single largest fault issue with FTTC.

In reply to a post by Chrysalis:

from the cabinet is about 370m

The issue with ali as I understand it is 2 issues.

1 - it corrodes on joints.
2 - compared to same thickness of copper it has higher attenuation, however not all copper matches the thickness of ali deployed, so e.g. 0.6mm ali should beat say 0.1mm copper.

Some more info on my current pair.

I had a recent fault at the cabinet, and there was short periods of time I had less crosstalk and my attainable increased as a result, it was at times over 100mbit. I dont know if this was with no crosstalk at all, but certainly less crosstalk
Before the fault however my attainable was less than 70 (6db snrm), interestingly after some discussions with openreach I know only the tie pair ordering got changed not the D side, so I heave learnt the tie pairs themselves can have a huge affect on crosstalk, and those are brand new copper.

I think we tend to generalise about aluminium in the network. And that�s because most of it on the network is the really thin stuff. Very, very thin. We see a disproportionately high about of faults in the underground network where you can basically pull apart the join between two bits of aluminium or aluminium and copper.

There�s some of the nice thick stuff around but you still get the problem with the poor joints between wires which just doesn�t happen much with copper. I can only put it down to the aluminium going brittle somehow as most of the time there�s no water involved and the joints are dry. It just isn�t good for a telecoms network.

When I had my long conversation with the BTO engineer a couple of months ago that was effectively the point he emphasised. The problem with aluminium was at the joints.

Brittleness, cracks and corrosion being the biggest issues concerning aluminium.

His statement to me was that aluminium joint issues were very common and problematic.

Elements of the BT/BTO management seem to consider this a non-existant or minimal problem (by area at least) according to an interesting story he told me.

In reply to a post by TygerTyger2010:

When I had my long conversation with the BTO engineer a couple of months ago that was effectively the point he emphasised. The problem with aluminium was at the joints.

Brittleness, cracks and corrosion being the biggest issues concerning aluminium.

His statement to me was that aluminium joint issues were very common and problematic.

Elements of the BT/BTO management seem to consider this a non-existant or minimal problem (by area at least) according to an interesting story he told me.

It�s increasingly getting changed for copper in some areas now. Areas where there�s small lengths of a few hundred metres here and there. But yeah, it�s all about the joints.

Unfortunately in others there�s so much of the stuff that it would be prohibitively expensive to replace.

I am not saying ali cannot be to blame, however I think the danger is when it exists its automatically assumed to be the problem and it prevents an investigation, engineers have a motivation to close jobs quickly, and having ali on the cable gives a convenient excuse to pass on to the end user.

My E side has thicker copper than my D side but has no relevance on FTTC.

On the D side info I was given a couple of years back had it at 0.2mm copper and 0.7mm (last 50m) ali.

The best copper seems to be mainly used for long runs in rural areas, alot of city areas seem to have thinner copper.

Edited by Chrysalis (Fri 18-Aug-17 11:03:32)

That was the case, longer rural runs would get the really thick copper. However when cables are renewed nowadays they only seem to use one gauge of copper.

yes but most of the network isnt getting renewed. They will only swap out cable if there is a reason to. Someone not happy with their sync speed typically wont qualify.

Edited by Chrysalis (Fri 18-Aug-17 11:10:43)

>>The best copper seems to be mainly used for long runs in rural areas

A phone line would be planned to be well under 500ohm single wire resistance when the network was built so wire poundage will reflect this.

Smaller gauge wires in main side cables are often smaller gauge because high pair count cables have to be able to fit in the ducts!

Original aluminum cables from the fifties were specced at 0.8mm as it has about the same resistance as 0.5mm copper. These were often directly buried alongside ducts to save duct space!

Hi there,

can someone please see this pic and tell me if this is a gpod cabinet and not just a fibre extention ?

is this a gpod

That indeed is G.fast.