prep ducting for future fibre install

hiya

I've just installed a new front door and just about to render front porch and interior plasterboard door surround, and I am looking for advice on prepping for a fibre install with ducting.

I've got the chance to run some 25mm inner diameter green (ex virgin media) ducting through the porch behind the render, past the outside of the door frame and turn down 90 degrees to the cellar where my existing BT line terminates and where the rest of my kit is. This means I will hopefully have a super neat install when FTTP finally makes an appearance in my area ... no cable clipped on wiring.

We have an overhead BT line at the moment, so after reading around, the chances are that BT will run the fibre overhead.

What diameter is the fibre 'cable'?

Rumours are that BT will only run through grey ducting, if I prep well with an accessible junction box for a 90 degree turn, I'm pretty sure that BT will run through the green ducting if I grovel nicely?

thanks for any advice

If your proposed ducting turns down to the cellar, could water also get in that way? My fttp was run through 20mm corrugated conduit that I ran up the outside wall and into the loft thence to a cupboard in the middle of the house so OR engineers are usually ok with ducting if it makes their job easier. Of course you might get an awkward one but all the ones I have spoken too whilst installing my and my neighbours fttp have been helpful.
PS. I get digital voice turned on today as well!

I used standard 20mm OD whote conduit with swept bends not sharp corners and in a couple of places formed 30 degree bends. At te soffit end, I used flexible ridge conduit for around 300-400 mm. A couple of pull cords and all was fine.

I would suggest avoiding using the green conduit as it does mean "fibre company" and you may get an objection. Don't chance it and run in conduit . much easier to use, smaller and easier to hide.

Thanks, think I will use smooth wall PVC conduit as you suggest. Googled it and only need to buy a bending spring to get a 30 degree bend around the door frame, I'll buy a swept bend seperately as I have some PVC solvent cement for plumbing jobs. Will try and fit in 25mm for an easier tug when fibre finally arrives.

Thanks for the reply

Water is well out of the way

The existing BT copper terminates in the cellar so I can't see them objecting to a fibre termination there.

It's a victorian house and the cellar was quite damp before refurb, I partially tanked it (paint on) to slow down damp ingress and have a dehumidifer with a pump to push water outside. Keeps it nice and dry

Make sure you get the right spring. Two grades of conduit Heavy and Light which have different wall thicknesses and hence different springs. I tend to use MT https://www.marshall-tufflex.com/shop/conduit-system... scroll to teh very end and you will see Light and Heavy springs for 20, 25, 32. Put the spring in place, and warm with a hair dryer whilst rotating the conduit then as you bend it pull the ends gently to avoid kinks and creases.

I did not weld mine - which, meant I could pull apart at one point where there was a complex set of bends to go through a wall, if needed. The cable is small and 20mm was fine, but if you will feel more comfortable with 25mm that will be OK. And if you want there are "Inspection Bends" so you can help it round and then weld the covers on. Just don't put tight elnows in.

At the end I fitted a standard square backbox, with a female adapter at the out - it allowed for a few extra coils to be put in there "just in case"

In reply to a post by MHC:

Put the spring in place, and warm with a hair dryer whilst rotating the conduit then as you bend it pull the ends gently to avoid kinks and creases.

Fantastic advice, will store that somewhere in that back of my brain for future use

Edited by deleted (Tue 08-Feb-22 11:26:52)

Or a hot air paint stripper or heat-shrink gun - but with those extra care is need to ensure it does not overheat. And as I mentioned - the right spring or it will kink.

I'll put the blow torch away then

In reply to a post by dect:

I'll put the blow torch away then

That is useful for burning the fumes from solvent welding and stopping you floating on cloud-9.