This topic

Convert BT line to ethernet for fttp install?

Mikert — Mon, 13 Apr 2026 06:39:03 GMT

I have an upcoming fttp install booked for next week, and an trying to plan ahead.

Currently BT line comes into loft from pole outside house, into master socket (in loft) linked to downstairs slave, where router is now.

Would it be feasible to convert these BT faceplates to ethernet sockets, so the ONT can be in the loft and keep the router downstairs in it's current position utilising these ethernet sockets?

I'm anticipating installer not happy going into loft, but he won't need to if he pushes enough cable in to reach the hatch.

I really don't want cabling coming down the front of my house if it can be avoided.

Thanks in advance 🙂

Re: Convert BT line to ethernet for fttp install?

iniltous — Mon, 13 Apr 2026 07:49:56 GMT

I can’t follow your train of thought , if you (correctly) assume the installer won’t enter the loft , then how does the potential conversion of the master socket in the loft and extension socket downstairs ( and the connecting extension cable ) into a makeshift Ethernet ‘patch’ help , assuming that can be done which isn’t that likely if the cable is standard telephone extension cable , the ONT will still be outside of the loft , somewhere accessible from outside of the property and near a power outlet, you then need to provide your own way of connecting the ONT to the master socket in the loft (that’s hopefully now an Ethernet socket ) , how do you get a ‘long’ Ethernet cable from the ONT to the loft ?, this isn’t the installers problem, and they won’t leave the ONT unmounted on a long lead so you can move it around at your leisure…it will be fixed in place as will the cable from the external CSP block .
If your router is downstairs anyway , it seems weird to no simply place the ONT downstairs, which means the cable from the pole running down the exterior of the property , you say the if the tech can pushes enough cable in to reach the hatch , what cable do you think this is ?

Re: Convert BT line to ethernet for fttp install?

Mikert — Mon, 13 Apr 2026 08:32:32 GMT

Thank you @iniltous for swift reply.

You obviously are more knowledgeable than I on these matters, but here are my assumptions which I'd be grateful if they could be confirmed.

I assumed the fibre cable would/could come into my loft using a similar route as current copper BT line.

2 metres away from wall is the hatch which this fibre cable could come to, to be terminated to the ONT.

ONT could plug into the newly converted (8 wire cat5e in use already for master to slave) ethernet socket (10cm from hatch, along with electric socket)

Router could stay in current position, but plug into the other end, newly converted ethernet socket.

Thank you 👍

Re: Convert BT line to ethernet for fttp install?

Mikert — Mon, 13 Apr 2026 08:02:48 GMT

So I just re-read your reply.

Are you saying the ONT will be outside the house and NOT in the loft as I'd hoped?

And just to add, I'd be converting the sockets to ethernet before installer arrives.

Re: Convert BT line to ethernet for fttp install?

imjolly — Mon, 13 Apr 2026 09:24:33 GMT

normally the fibre cable from the pole to your home at roof level will then run down the wall to ground level to the CSP and then through wall into your home and connected to the ONT. If your loft is not floored and accessible then unlikely installer will fit anything in your loft

Re: Convert BT line to ethernet for fttp install?

iniltous — Mon, 13 Apr 2026 10:05:23 GMT

The ONT is a mains powered internal box that the router connects to with an Ethernet cable , the one supplied is around 1.5m in length , hence normally a double power outlet is needed as the router will be very close to the ONT .

If I make a few assumptions about how I think you think you could have your service installed and how it actually needs to be installed , the cable from the pole comes via the CSP , an external wall block where the cable from the pole is spliced to an internal grade optical cable that has a pre-fitted optical plug that goes into the ONT (so the ONT has an optical cable coming in , and an Ethernet cable going out to the router as well as a power cord . )

If the loft is out if bounds for the installer but you want the ONT upstairs minimum , and for arguments sake , the landing at the top of the stairs underneath the loft hatch is suitable , so the ONT is fitted there , you then need your own longer Ethernet cable , and be able to get it into the loft yourself , then you need to connect it to the master socket that you have converted to an Ethernet socket , and downstairs you connect the router to the extension socket that was also converted to an Ethernet socket ….the installer can’t push the optical cable plug into a hole that goes into directly into the loft and let you fit the ONT yourself , that’s why I think your ‘plan’ isn’t really possible , the ONT won’t be in the loft but outside it , how close to the loft can be known until the installer turns up , if that’s on the first floor that’s normally doable , so potentially less external cable visible but you have the problem of getting your own cable into the loft to use your converted sockets .

If you convert the master socket and extension socket to Ethernet in advance your existing broadband won’t work unless you move the router to the loft and separate the incoming cable from the Ethernet extension.

Re: Convert BT line to ethernet for fttp install?

Mikert — Mon, 13 Apr 2026 12:36:48 GMT

Thank you all for your input.

So I understand now it seems very unlikely.

But, ever hopeful, I will convert the BT sockets to ethernet. It will cost less than £10, and take less than an hour on the morning before installer turns up in afternoon. So I'm quite happy to ask, but prepared for not being able to. Not a lot to lose.

I have read the router can be up to 100m away from the ONT so I'm well within that.

Everything will be ready, It's just hoping he will be happy with the ONT in the loft. BUT, I do understand how unlikely that is now. Although in my naivety I'll keep my fingers crossed and hope for the best.

Thank you.

Re: Convert BT line to ethernet for fttp install?

pddco — Mon, 13 Apr 2026 20:50:27 GMT

Just a thought. Looking at the point where the span from the pole to your house ends. Can you perhaps picture a different place where the span ends on the house? Could that make the external drop to a ground level CSP less obtrusive? You could then at least ask the OR person if it were feasible to do that as an option.

Re: Convert BT line to ethernet for fttp install?

WSH — Mon, 13 Apr 2026 21:15:11 GMT

I do love your optimism, my friend.

I assume, from what you’ve said, that the cable in place is already 8 wire, cat 5e UTP. Seems a bit over the top for a phone extension, but...

I’ve done this sort of thing for a living and even I wouldn’t count on that taking “less than an hour” and on getting it done immediately before the installer turns up. A few points:

You will need an IDC punch tool to connect the sockets. Have you got one?
You may well find the back boxes are not deep enough for RJ45 sockets. I’d check beforehand if I were you.
Yes, it will go a 100m…under ideal laboratory test conditions, top quality cable and a perfect install. Working practice is more like 80 to 85m
If you ever intend to be one of these people that wants silly speeds like 1.6 Gb or 2.5 Gb etc. you may find cat 5e isn’t up to it. Cat 6 would be better. Unofficially, cat 6 will handle 10 Gb/s at up to 55m.

Good luck.

Re: Convert BT line to ethernet for fttp install?

Mikert — Tue, 14 Apr 2026 10:56:00 GMT

Thank you again.

Yes 8 stand already there. The house was built with a few Ethernet routes in place, from router (in study) to Lounge (for TV & sky), and from utility (where rainwater comes in) to water tanks in loft. So I guess sparkly used the same roll for everything. The cable says Cat5e.

You're right about the loft backbox depth, loft one too narrow, but downstairs one in wall is ok.

A push tool arrived this morning along with the 2 x ethernet faceplates.

👍🙂

Re: Convert BT line to ethernet for fttp install?

Mikert — Tue, 14 Apr 2026 10:59:30 GMT

Yes thanks. There is a route planned outside that will be used if plan A doesn't work.

I'm not overconfident loft for ONT will happen, but fingers crossed.

Re: Convert BT line to ethernet for fttp install?

pddco — Tue, 14 Apr 2026 13:00:34 GMT

@Mikert Just something else to think about. Having the ONT next to the Hub (downstairs) or at least easily accessible , will make it very easy to see the status lights should you have issues with your broadband service.. And, if you’re continuing with a landline phone number, you could use a single backup battery unit if you so wished, to power both the ONT and the hub. May not be needed though I suppose if you’ve got a good mobile signal and/or ditching the landline.

Re: Convert BT line to ethernet for fttp install?

Mikert — Fri, 17 Apr 2026 14:20:10 GMT

So after work this morning, I have fitted both ethernet faceplates. The loft back box was actually OK as the faceplates are pretty shallow.

I have cut a patch Cat5e cable in half and used 2 strands to connect, and keep my internet going till install in 10 days.

I also paid ~£6 for a network checker, and all good.

If I can persuade installer to push a few extra metres so it can reach landing under loft hatch, it's just a case of plugging in the NTO upstairs. There's a vertcal board there ready to fix it to along with double electric socket.

Just hope it wasn't a waste of a few hours

I live in hope, Thank you 😊

Re: Convert BT line to ethernet for fttp install?

WSH — Fri, 17 Apr 2026 14:26:17 GMT

"...and used 2 strands to connect..."

I may have picked you up wrong, but ethernet will needs all 8 wires.

Re: Convert BT line to ethernet for fttp install?

Mikert — Fri, 17 Apr 2026 14:38:02 GMT

Yes, all 8 connected to ethernet faceplates, and checked all connected good.

But both have a patch Cat5e cable plugged into them, with 2 strands of those connected to main incoming BT copper cable in loft, and other connected to BT box.

Re: Convert BT line to ethernet for fttp install?

iniltous — Fri, 17 Apr 2026 15:57:17 GMT

You still haven’t answered the question , what cable do you want the installer to ‘push a few extra metres so it can reach landing under loft hatch’ ?, although you appreciate now that it’s unlikely the tech will enter the loft I’m not sure you realise what the installer will do and how they will leave the installation , but it will be with the ONT fitted (secure) on the wall near a power outlet or electrical extension lead (outside the loft ) , and the optical cable from the CSP cut to correct length , and also fixed to the wall , that cable plugged into the ONT and the router connected to the ONT , so where is this extra cable ?, no extra cable can be left that you can then ‘uncoil’ and run into the loft yourself (presumably with you refitting the ONT in the loft after the installer has gone ) , if it’s the Ethernet cable to the router you want a few extra metres to reach into the loft , that’s your concern (if you don’t use the short cable that comes with the ONT ) .

Re: Convert BT line to ethernet for fttp install?

Mikert — Fri, 17 Apr 2026 16:08:17 GMT

"what cable do you want the installer to ‘push a few extra metres so it can reach landing under loft hatch’"

Happy to be corrected, but as I understand, there's a CSP on wall outside. There's an optical cable coming into the building to connect to an ONT, and the ONT is connected to the router with an RJ45 patch lead.

The cable I'm talking about is optical cable, CSP to ONT. With ONT in loft, (hopefuly) next to mains sockets, and ethernet wallplate, located at the hatch opening.

The tech will have no reason to enter the loft, unless he wants to pop his head in to take a look.

I hear you loud & clear you stating it's not going to happen. But I'll just wait & see now. Nothing to lose.

Thank you again. 😊

Re: Convert BT line to ethernet for fttp install?

iniltous — Fri, 17 Apr 2026 16:53:59 GMT

So to clarify, your hope is the installer will pass the optical cable from the CSP with the factory fitted SC/APC plug through a hole directly into the loft space from outside pushing an extra few meters through enabling you to run that optical cable inside the loft space , with you fitting the ONT and plugging the cable into the ONT ?
I’m not saying that’s impossible but very unlikely

Re: Convert BT line to ethernet for fttp install?

Mikert — Fri, 17 Apr 2026 16:57:10 GMT

Yes, basically, but the optical can be connected to ONT from the landing if long enough.

Thanks again.

Re: Convert BT line to ethernet for fttp install?

WSH — Fri, 17 Apr 2026 17:46:01 GMT

Fibre’s a whole different ballgame to copper. There’s a much bigger bend radius to take into account, for a start.

Draw weight is a lot lower as well.