FTTP deployment - one for the engineers?

Our village is having FTTP rolled out. It is already well over a year behind schedule; however small areas have now been released, all of which are "ducted" properties. There seems to be a problem with the pole based properties, but BT are very vague as to what it is. They have identified what appears to be a subset of the pole based properties for which they say an "aerial solution" is required., and that this technology is "still unproven", so that any deployment is likely to be months away at least. Now as far as we are aware "aerial" simply = "pole-based", and is in itself far from being "unproven technology", so they must be referring to something else. They have previously mentioned "shared services" poles, but again that does not seem to us to be "unproven technology", simply a requirement for engineers to have the requisite safety certificates before shinning up a pole with a live electricity cable at the top.

There have been many meetings with senior BT representatives, but none has been able to explain satisfactorily what differentiates these properties, or what this "aerial solution" is.

So the question is - what are BT talking about?

the aerial solution would be a microduct or whatever strung from a pole. ie an overhead fibre feed. What you regard as a proven solution may not be seen the same by them perhaps ?

How many of the poles are shared ?

In my village, Whitchurch in Hampshire, where some of us are destined for FTTP, BT's contractors have been adding ducts and new chambers for the FTTP fibre and equipment. In one place, where they have added a new chamber close to a shared pole, there is a new grey tube sticking out of the ground at the bottom of the pole with a blue rope emerging from it. Based upon that I assume that BT will pull the fibres from the chamber to the pole through the grey tube and then distribute them from the top of the pole. Exactly how they will do that is something that I will watch with interest if they ever get as far as deployment which, if the e-mail from another thread here is true, will happen within the next couple of months.

Now as far as we are aware "aerial" simply = "pole-based", and is in itself far from being "unproven technology",
Pole-based copper is certainly proven. I believe there are unproven details with pole-based fibre; possibly (guessing) because while copper is more prone to electrical noise, fibre is more prone to light noise.

I'd imagine that they are referring to the point that long term stringing of fibre optic supply cable along multiple poles is indeed unproven in the UK.

If it was even considered for my area in the future I'd think them mad. There is so much debris from trees coming off and flying around in only a modest gale much less a storm the fibre would have to be within a pretty rugged 'bomb proof' sheath.
The overhead electric cables round here are aerial bundled cable (ABCcable - all 3phases plus neutral in one twisted insulated bundle) which are strong enough to actually withstand a medium size tree coming down on them without breaking or being damaged.

Can you say the same about a fibre optic cable?

an aerial fibre deployment uses a small bore tube down which the fibre passes I presume, or some special composite fibre cable (possibly fibre & copper together) that can carry the tension / wind load without stressing the fibre itself.

I think Andrew posted some photos of FTTP on poles in Cornwall somewhere.

In reply to a post by yarwell:

How many of the poles are shared ?

Difficult to tell how many also have electricity services on them - many of the poles are hidden away in people's gardens, behind hedges etc. Only when you start looking for them do you realise just how many poles there are! However one of the roads which they have specifically mentioned has no shared poles at all.

A lot of the poles DO already have fibre run all the way to the top; it doesn't make sense to get that far then announce they can't go the last few metres because the technology is untested!. We understand that there is a small area elsewhere on the exchange where properties have had fttp delivered from a pole.

We wondered whether the maximum drop for a fibre cable is shorter than for copper, putting some properties out of reach from their pole and necessitating some other solution?

In reply to a post by zom22:

Can you say the same about a fibre optic cable?

...or indeed a bog-standard copper cable? Surely there's only one way to test the long-term resilience of an overhead fibre cable?

In reply to a post by yarwell:

I think Andrew posted some photos of FTTP on poles in Cornwall somewhere.

Yes he did in this post.

There are many of these on poles in quite a few parts of the town, and although the pole outside my house has had the fibre cable run up it and the manifold fitted, I'm still waiting impatiently for the FTTP service to go live in my 'cabinet area'.

I have managed to narrow down one approximately 200m length of one of the main roads (Henver Road, Cab 81) where FTTP is already available and that particular section is serviced via poles, although I don't know of any premises actually connected. Strangely not all the premises along that road which are also in the 'cabinet 81 area' are yet able to obtain FTTP which I have reason to believe has been available in that area for some months (according to a friend).

Edited by Rastus (Fri 17-May-13 11:33:34)

I've seen some of the specifications for copper drop cable that refers to it as OK to "cross" low voltage power lines - which I presume is rather different from running parallel to it.

I expect, therefore, that the spec for fibre microtubing might have similar differences. And BT's confidence in how it performs in reality might not be high.

Deploying FTTP *in the UK* and for *mass residential use* is relatively new, and relatively unproven. We're not talking about the technology here, but the methods of deployment, the training of the staff, and the impact of both on the future maintenance of the equipment.

So deployment of FTTP is, so far, a large-scale trial for BT to learn all the various gotcha's as they apply to the current environment in the UK, with regard to all kinds of legislation, health & safety, union rules, training and things such as weather, and the future impact to callouts and interaction with other utilities.

All of this plays it part in determining whether a FTTP rollout is profitable, or worthwhile at all, so you have to expect that they want to make sure they have learnt the right lessons as they go. If they don't, then FTTP deployment will be killed for decades...

Surely there's only one way to test the long-term resilience of an overhead fibre cable?

Yes. Both the microducting for blowing the fibre, and the fibre itself.

The manufacturer builds it to a spec.

BT install it at Martlesham Heath for a while, to see how it performs in reality. They get opinions from engineers about how it degrades over time, and how it performs in a degraded state. How maintenance is affected in a degraded state, and how a neighbour's line works when they order it ten years later.

When they're convinced it will survive for decades, and their staff can handle it, and that it deserves to be a real part of the future deployment, they can put it to the test in one or two live locations... and go through similar tests.

What they really need to ensure is that they aren't going to accidentally cause bad fragmentation of the stuff that gets deployed. If that ends up true, then they ensure they have a training nightmare in 30 years time.