FTTP internal fibre size

Openreach have been doing lots of work around my area (weekends, late at night), installing their FTTP infrastructure and appear to now have some light on it as they were around checking light levels today.

There is an 8-way Optisheath Multiport in the pavement chamber that's about 3ft from my front path. I'm on a new (well, newish) estate so have tube from the pavement chamber to my front wall.

I'm trying to understand the installation process as my current copper NTE is just inside the front door and isn't an ideal location for the ONT (there's no power there for starters).

I'd like to have the ONT in my "computer room" which is upstairs. I've run some fibre tube from the master socket to the computer room (2 x 3.5mm tubes) but am trying to find out whether this is big enough for the fibre to fit through - if not, I can replace it but would prefer to do that sooner rather than later so it's all in place for the installation

This leaves me with the following questions:

Do Openreach still have an external splice point?

What's the diameter of the internal fibre?

If anyone knows the answers it would be greatly appreciated. I've made some enquiries with some Openreach colleagues who I deal with through work. If they come up trumps then I'll post the answers here, however they're mostly dealing with leased lines so don't have knowledge of the FTTP kit.

Many thanks,


Neil.

External splice point is preferred choice these days.

The fibre ran from inside to the outside has two diameters

white indoor part measures at 3mm diameter
with black outer sheath 5mm diameter

3.5mm tube seems far too small, if it was a piece of blown fibre which is much thinner then would be fine, but connectorised stuff is designed to cope with some push/pull so has tougher outer.

That's great information Andrew. Many thanks. Good job I checked!

I know that the fibre tails that Openreach use for leased lines fit through it (which would be 3mm) but if it's with the outer sheath then I'll have to sort out something else for it to run through.

I'm able to get some Copex but thought that may be a little tricky to pull it through!

Thanks once again.

https://www.openreach.com/content/dam/openreach/open...

Goes through what is expected in new builds.

whatever you put in put a draw rope in as well. i used 20mm flexi conduit

The internal fibre is usually about the same size as internal 2 or 3 pair copper cable. Your 2 x 3.5 tube sounds like what is used for blown fibre in commercial buildings for leased lines, etc.

If you’ve managed to get the fibre tube in place you could probably also get some 20mm flexible electrical conduit in its place (Screwfix sell it). I’d get a strong nylon cord threaded through it so it makes it easy for the engineer to pull the fibre cable through it on the day.

It seems most installs are now using an external CSP again.

Many thanks. I'll have a good read of that. I've had a quick flick through it already.

Thanks for the advice. I can use the tube that I've installed (I couldn't possibly confirm nor deny that it's blown fibre tube) to pull anything else through!

The tightest bit will be where it heads upstairs - there's a small gap beneath the plasterboard, between the floor boards and wall - that may take a bit of work to get a bigger tube through!

Many thanks once again.

Pulling a 3mm cable through a 3.5mm tube (assuming that's the inner diameter!) is an extreme ask. That's unless you're talking about blown fibre, and even then it's not just any old tube you need.

I provided 20mm round pipe, and that made for an easy install. I think you should be safe enough with 16x10mm (outside dimensions) oval electrical duct, which is cheap, low profile, and can be chased into plaster if needed: e.g. https://www.tlc-direct.co.uk/Products/MTOV16.html

Make sure you have a draw string in it in advance, and keep any bends as gentle as possible (no right-angled connectors).

Good luck with the installation!

Edited by candlerb (Tue 29-Sep-20 17:09:36)

I think you can also get 16mm flexible conduit but you’d need to check how easy that would be to pull through.

Is your tube black (with yellow stripe, for external duct use) or white? Think the designation for the white internal tube is ‘CW1803’, would be printed along it. The black stuff is also extremely stiff!

It would have to have been pushed through the tube, not pulled! 3mm fibre tail fit quite nicely through 3.5mm blown fibre tube!

I shall investigate my options and get something more suitable in place. Screwfix are just around the corner so I have easy access to whatever they have! I deal with fibre in a corporate environment most days so know to respect it and the issues with bend radiuses, etc.

I haven't repaired the holes in the ceiling yet (the rods would only go so far) so it's not going to be an issue installing something else. I'm tempted to fit ceiling access covers like this: https://www.toolstation.com/access-panel/p63127 at least until the room gets redecorated!

Fingers crossed it won't be long and the buys will have an easy installation. I will have the chocolate Hobnobs on standby but I don't know whether they're allowed to accept them now! ;-O

The black, external stuff is mighty tough, the 4 tube is even worse! It's the white internal stuff (I think that has to be used internally because of the fire rating) - and it's much more flexible.

It doesn't appear to have a CW number - isn't CW1308 copper phone cable? It's just Mark 3 BFT.

I shall be perusing the Screwfix catalogue shortly!

Many thanks.

Pretty sure CW1803 is correct - remembered it as just transposed numbers from the white internal copper.

If you were to use the screwfix 20mm flexible conduit (there’s black or white) there are matching couplings that could take you neatly into a double electrical back box in a similar fashion to what’s in the developers guide. Then get a faceplate with a brush centre to bring the fibre out through and you could end up with a very tidy install!

Apologies, I completely misread your post! I read it as CW1308 (which is copper phone cable)! Googling CW1803 does seem to show up as BFT. The drums it comes on are made by Emtelle, part no. 6034 but no CW on the tube or drum!

I should be able to acquire some 20mm tubing (Copex) so will endeavour to get some fittings for it. I'd planned a single gang box with brush plate - do you know whether it needs to be a double? I'm not planning for the ONT to be fitted over the top of it as it's not the best place for it to be installed!

Thanks once again.

Yes, there’s an external splice point.

2.9mm is the internal fibre size .... I personally feel what you have fitted is a tad tight.

Many thanks for the extra info. I shall investigate some replacement tubing. I may leave the existing stuff in place, then the engineer can use whichever he wants!

I know that normal fibre tails fit through the BFT but that's normally over just a short distance (between cabinets). I reckon that this is ~10m (I'm waiting for some strimmer line to push through to check the length)!

Thanks once again.

I’d go for a double as more room and easier to bring the fibre out without any severe bends, etc, plus you might be able to coil any extra length in the box.

At some point I’d hope to do something similar - no FTTP here yet except for some BDUK going out of town on my cab area.

Don’t forget to fit a pull cord through.

I shall get a suitable back box in the next couple of days and get that fitted as soon as the replacement tube is in! Thanks for that.

I have to say that I'm amazed that I have the opportunity (well, soon) of getting FTTP. I'd seen Openreach around the estate, pulling some fibre through and just assumed that one of my neighbours had paid for a leased line (although I couldn't see it entering any of their houses). Then, on the Thursday Openreach announced that they were going to cover the town. On the Friday (literally the next day) I managed to chat to one of the engineers who confirmed that they'd pretty much finished the installation and were just labelling things up! The headend still needed to be done and it was actually going to be in our local exchange!

Whilst they were installing the fibre, Telent were standing up another FTTC cab on the PCP (that I'm connected to) as the original was out of capacity! The fibre guys couldn't understand it either!

I'm certainly not complaining but it seems a case of left hand and right hand! It defies logic but the estates around here are relatively new (mine is ~18 years old) so the ducts are good and it's an easy job. I guess Openreach are targetting the quick wins!

I will definitely make sure of that. Many thanks.