long r.o.w fibre in duct

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unpc

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Wannabe Geek

#255523 16-Aug-2019 05:57

I have a very long r.o.w servicing several properties. There is an existing presumably 20 mm duct with one phone wire running to an access point. Three questions from the road to that point does each property require a separate cable or can multiple fibres be split into cables at that point. How many cables can fit into one duct? I understand that where there are right angle connections these need to be replaced by curves. Wouldn't that be standard procedure?

cyril7

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#2300101 16-Aug-2019 06:29

Hi, not enough information to go on, but tyically each 20mm duct carries phone cables for a single property, and so it is with fibre, a single blow tube is installed in each 20mm duct (if it exists and is usable) and fed to each property, typically only one two pair copper cable goes in a single 20mm duct, but its not uncommon to have 2 or 3 if more li es are needed to a property but never split between properties, I suspect fibre would only allow one blown tube per duct.

Only one fibre bundle is blown into a single tube, its impossible to put more than one fibre bundle in a tube, however bundles are typically 2 fibre cores to each residential (one fibre for Chorus, other as backup or Layer1 unbundling). However blown fibre bundles can be upto 12 fibre cores for commercial buildings, a fibre bundle is between 1.0mm diameter for a 2core and 1.3mm for a 12core.

It is possible that a 50 or 80mm duct runs down the row and 20mm ducts are tee'd of this with proper angled tees, if this is the case and the tee's have not come away from the main duct then it should be possible to pull a fibre duct to each property.

But I suspect from what you tell me there is a 20mm duct to each property with right angle bends, if its proper Chorus 20mm duct there are no right angle bends only swept bends, which if installed correctly it should be good to go assuming no snags.

Maybe a bit more information and perhaps a simple drawing of the layout.

Cyril

unpc

4 posts

Wannabe Geek

#2300478 16-Aug-2019 15:33

Sorry about the lack of detail.

There is a main duct running about 170m to a plinth. I cant determine the size without digging it up At the plinth it feeds in through 20 mm then out to 4 properties It contains a cable of about 10mm ED with multiple pairs.

I also can't determine if the correct curved joins were used by chorus about 8 years ago without cutting concrete / digging the join up.

I calculate 4 cables 3.5mm id 7.3 ed would fit in the existing duct with the existing copper cable removed but am not sure if they would otherwise.

I would prefer to avoid approx 170 m of microtrenching through reinforced concrete with other parts minimally buried like 50mm. I think 4 cables would be quite intrusive and weaken the concrete. Thanks.

cyril7

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#2300482 16-Aug-2019 15:38

So, let me get this, at the Chorus pillar (ie street front) there is a 25 or 50 pair feeder that drops off four pairs, one for each property. This now goes into what exactly and appears at each property as what a 20mm duct with a single dual pair cable.

still a bit confused, a quick sketch might help, but hauling anything 170m is going to be an issue.

Cyril

unpc

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Wannabe Geek

#2300489 16-Aug-2019 15:55

No. there is no pillar at the street. The pillar is about 170m down then it distributes to 3 sections one being a 2 house property.

cyril7

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#2300492 16-Aug-2019 15:59

Ok, and the feed into the Pillar is a 20mm duct or larger, and was it installed by Chorus or privately, is the pillar a chorus one, is it labeled local or is it fully part of the network

Cyril

unpc

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Wannabe Geek

#2300668 17-Aug-2019 05:48

Oops servicing I was wrong. The plinth at the street feeds 2 ducts the original serving 5 properties on 100 m. The second duct was laid for me servicing the rear 100m and 3 properties.

My memory possibly wrong was that new duct was larger than 20 mm. However the rear plinth and the uprights which are 20 mm were installed by chorus as were cables in the 20mm ducts to the 3 new sections.

I imagine the whole network vests in chorus, although the ducts were laid privately.