Damaged the fibre cable in your home? What next

On Openreach Full Fibre, the network used by BT and many other providers, Openreach describes three pieces of its kit that can be in your home:

• The ONT (optical network terminal): a white box labelled Openreach. It turns the light signal in the fibre into a connection your router can use. It is not a router and doesn't give you Wi-Fi on its own.
• A power supply unit (PSU) that powers the ONT from a mains socket.
• Internal fibre cabling and wall fittings: the cable and fittings that bring the fibre in from the outside wall. Openreach calls these fixed infrastructure that shouldn't be moved or altered.

In our view, the thin lead running to the ONT is often the most exposed part, because it can sit where a vacuum, a chair leg or a paintbrush can catch it, or where a pet can reach it. Other full-fibre networks have their own versions: CityFibre, for example, mentions a cable, a "toby box" and an ONT. Our guide to full fibre equipment: the ONT and your router explains each box and what its lights mean.

Whose equipment is it?

Not yours. Openreach says its ONT, power supply and internal fibre cabling belong to Openreach, not to you or your provider. Hyperoptic's and Gigaclear's terms say the same of their equipment. So it isn't yours to repair, and the owner's rules decide whether damage is charged.

Sometimes it's obvious: a lead chewed through, crushed under furniture, pulled from its wall fitting, or a box hanging off the wall. Other times the internet just stops, and the ONT's lights tell you why.

Lights that point to the fibre

• PON off, or PON and LOS both flashing. BT says this means the fibre link isn't connected or there is a problem between your property and the exchange. BT's advice: check the fibre cable is inserted and undamaged, then restart the box and give it five minutes.
• A PON light that keeps flashing. Brief flashing is normal: BT says a flashing PON with LOS off means the box is verifying its connection with the exchange, so wait for solid green. If it never settles, suspect the fibre.
• A red LOS light. Openreach says no lights, a flashing PON light or a red LOS light may mean a connection issue, and that a red light or no power light may mean an engineer needs to visit. (LOS stands for loss of signal.)

A working Openreach ONT shows green Power and PON lights and a green or flashing green Port/LAN light, according to Zen. Layouts vary by model, so check your provider's help page.

Fibre carries your broadband as light through fine glass, so a damaged lead can't be patched like other cables.

• Don't unplug the fibre lead from the ONT. BT's help says the green optical cable "should have been connected by your engineer. Do not unplug it." The only check BT suggests is that it is fully inserted.
• Don't look into a cut or loose fibre end. The Fiber Optic Association, a US training body, says the light in fibre links is infrared, so you can't tell by looking whether it's there, and never to look into a fibre end unless you're sure nothing is lit at the other end. It's general fibre-safety advice; we found no UK consumer rule on it.
• Don't handle broken fibre ends. The same body says the bigger practical risk is the glass itself: broken ends and scraps are extremely sharp, can get into skin and are hard to remove, and are very hard to flush out of an eye. Treat them like glass splinters.
• Don't tape, glue or try to join it. The Fiber Optic Association describes joining fibre (splicing) as technician work with specialist tools. Whether your lead is joined or replaced is for your provider and the engineer to decide.
• Don't bend the lead tighter. Openreach's March 2021 guide for housebuilders installing its cable gives a rule of thumb: internal fibre cables must not be bent tighter than a £2 coin. If yours has a sharp kink, leave it as it is and mention it when you report the fault.
• Don't move, remove or open the ONT. Openreach says removing or tampering with it could interrupt your connection and could result in a call-out charge to have it reinstalled.

1. Keep pets and children away from the damaged section, especially if there's a broken end or loose glass. Shut the door on the room if you can.
2. Leave it in place. Don't pull the lead out of its fittings or take the box down, even if it's hanging loose.
3. Take photos of the damage, the ONT lights and where the lead runs. (Our suggestion: it gives you a record if a charge is discussed later.)
4. Report it to your broadband provider. Openreach doesn't take repair bookings from households; it says providers raise repairs with it. CityFibre likewise says its connected customers contact their provider, because the contract is with them. With your broadband down, use a mobile, your provider's app over mobile data, or web chat.
5. Ask whether the visit could be chargeable, and how much, before you agree a date (see below).

What to tell your provider

• That the fibre lead or ONT is physically damaged, and how (for example, chewed by a pet).
• Which lights are showing, and what you've already checked.
• Whether anyone relies on the landline: Openreach says that on Full Fibre the landline is a digital line through the router, so it may be down too.

When it's not a job for your provider

• Damage outside, such as an exposed or dangling cable, a damaged cabinet or a leaning pole, goes to the network. Openreach takes these reports by web chat (7am to 7pm daily) or on 0800 023 2023 in an emergency or out of hours, though if your service is down your provider still raises the repair.
• Damage the network's own staff caused has its own route. Openreach takes reports of damage its staff caused to your property through its web chat, and claims by email to its claims handler. Hyperoptic's and Gigaclear's terms both commit them to put right damage their own people cause at your home. Our guide to damage caused during an installation sets out the steps.

Possibly, so find out before the engineer arrives. No provider we checked publishes a single price for repairing a fibre lead its customer damaged. Openreach leaves the answer to your provider: it's the provider that tells you whether a charge applies, based on the type of fault and your service agreement. What the terms do say is when a charge can apply, and for most of them, damage you or someone in your home caused is one of the triggers.

You can see each provider's current packages on pages such as BT broadband deals, Sky broadband deals and Virgin Media broadband deals.

Two things work in your favour. First, if the box failed on its own, that's not damage: Sky's terms, for example, cover fair wear and tear on the ONT, and our guide to faulty broadband equipment and your rights covers what you're owed. Second, a charge isn't automatic: most of the terms above describe it as something that "may" apply, or that the provider confirms or agrees with you beforehand. Our guide to engineer visit charges covers the wider rules.

These steps combine the networks' own rules with our practical suggestions:

• Know where the cable runs. Gigaclear's terms ask you to know the route of its equipment across your property and point it out to anyone working there. It's worth doing on any network: show your decorator or electrician the route.
• Work around the fittings. Openreach describes the internal cabling and wall fittings as fixed infrastructure that shouldn't be moved or altered. Our suggestion: mask them off rather than painting over them, and don't bury them behind new boxing without asking your provider first.
• Keep the power supply plugged in. Openreach says that if the PSU is unplugged, your broadband stops working. If a socket has to be switched off while work is done, expect to lose the connection until it's back.
• Don't relocate it yourself. If the ONT or lead is in the way of a new kitchen or wall, ask your provider to move it. CityFibre says customers with a live service should ask their broadband provider to relocate its cable, toby box or ONT for renovation works. Its page doesn't mention cost, so ask whether the move is charged before you agree a date.
• Think about pets. If you have a young dog, a rabbit or a cat that chews, ask your provider whether the lead can be routed or protected out of reach.

Planning a bigger project? Our guide to broadband during a renovation covers moving the line, planning Ethernet cabling and choosing where the router and ONT should live.

1. Ask for the reason in writing. Openreach says that when its engineer finds the problem lies beyond its network, the reason goes in the engineer's notes, which are shared with your provider. Ask your provider what the notes say.
2. Send your evidence: photos, the lights you saw, and whether a charge was mentioned when you booked.
3. Make a formal complaint if the answer doesn't satisfy you, quoting what you were told about cost when you booked. For the details, see how to dispute a broadband bill and how to complain to your provider.
4. Take it to an ombudsman scheme if it stays stuck. Providers belong to an alternative dispute resolution (ADR) scheme, which is independent and free for you. Since 8 April 2026 you can refer a complaint 6 weeks after you first raised it with the provider (8 weeks if you raised it before that date), or straight away once the provider gives you a written deadlock letter.

If you were already planning to switch, get the repair done and any charge settled first, so the two don't get tangled. Under One Touch Switch you contact only the provider you're moving to, and your current provider must send you the switching information, including any early termination charges. On Openreach Full Fibre the ONT stays put: Openreach says the same box works with whichever provider you're with. If another network asks you to remove Openreach's equipment, Openreach says don't, and check with your provider.

When you're ready, compare broadband deals at your postcode, look at fibre broadband deals, or read about each company on the broadband providers hub. The deals come from our comparison partner; you order with the provider you choose.