Tidying POE splitter supply to FTTP ONT.

Jul 20, 2026 Last reply: 3 hours ago 6 Replies
P

I have just replaced my old copper BT connection with FTTP. The old BT master socket was by the front door. There is an ethernet cable from this to my router upstairs. Previously, the ethernet cable was just used as an extension to the telephone copper pair, but it is good ethernet cable, all neatly channelled into the plaster wall, going into a shared backbox with the BT telephone cable.



So I got the ONT installed at the old master socket, and used the existing ethernet to connect to my router upstairs.



The problem is I don't have a power socket near the ONT, so I power it by an active POE splitter.



The problem is the POE splitter is too big to hide in the existing backbox. I did think of putting in a double gang backbox, but the fibre optic cable looks very fragile, and I don't want to work around it.



So the question is how to smarten up/hide the POE splitter?



formatting link

I could possibly squeeze a passive POE splitter into the existing back box. I'm not sure if it will fit, and I would prefer to use active POE.



Maybe some kind of plastic box under the ONT to hide the active splitter?



Has anyone had a similar dilema?



Vote
Twitter Facebook LinkedIn
A

In fact the internal fibre is so-called "bend insensitive fibre" you could probably use it as shoe-laces without breaking it ...

Vote
Twitter Facebook LinkedIn
P

Internally, they appear to have stuck something bendy on the external fibre optic cable. However, I can't pull this back outside through the hole in the wall as the plug on its end is too big to fit through the hole. So if I want to channel out to fit a bigger back box I would need to work around it. The backbox hole would need to be 5mm deeper as well as extended to a 2 gang box. I'm pretty sure I have the talent required to break the bendy cable with a multi-tool or chisel.

Vote
Twitter Facebook LinkedIn
A

Put a larger adaptable box over the BT box?

You can get a "back-to-back" SC/APC coupler plus a suitable length of fibre to move the ONT where you want it ...

formatting link
formatting link
Vote
Twitter Facebook LinkedIn
P

A surrounding cabinet is OK, but a last resort. I might even try to get a small plastic box to sit below the ONT. I just wondered if there was a standard solution.

The BT Openreach installer said I would need an expensive splicer to move the cable, but I seem to remember a CityFibre installer telling me I could move the cable, but maybe I misremembered.

Anyway I quite like the ONT where it is, distinct from my network stuff. I would have put it in my garage if it had been easy.

Vote
Twitter Facebook LinkedIn
T

This bare board will fit in a back box:

formatting link
Reviews say it's 63x31x18mm.

It's expecting RJ45s are both edges, but perhaps you could solder your 'input' cable directly to the pins.

There are some other boards available, need to confirm they're:

  • active
  • gigabit
  • the right direction (PoE in, DC+ethernet out)
  • the right voltage (5V/9V/12V etc)

and some of those aren't immediately clear on other Aliexpress listings.

Theo

Vote
Twitter Facebook LinkedIn
S

No suggestions, but the real answer would be for BT to make an ONT that can be PoE powered.

Vote
Twitter Facebook LinkedIn

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required