- Openreach and alternative networks deliver full-fibre either overhead, using existing or new poles, or underground, by blowing fibre through duct, and frequently use a mix of both along a single route.
- Reusing existing poles and duct is a core part of Openreach's build approach because it speeds deployment and reduces the need for new street works.
- Openreach's regulated Physical Infrastructure Access product lets other operators reuse its ducts and poles, which is why several networks may share the same overhead or underground route.
- Street works on the public highway are subject to permit and notice rules under the New Roads and Street Works Act 1991 and related GOV.UK guidance.
- The PSTN switch-off means the old copper telephone network is being retired, with Openreach's all-IP migration completing in 2027, increasing the importance of fibre and IP-based connections.
Fibre reaches homes overhead via poles or underground via duct, often a mix of both. Overhead is quicker with less digging; underground may need a small trench. Operators reuse existing infrastructure where they can.
Last reviewed: June 2026
Two routes for the same fibre
When a full-fibre connection is brought to a property, the cable has to travel the last stretch from the network in the street to the wall of the home. There are two physical ways to do that: overhead, strung from a pole to the building, or underground, run through a duct beneath the pavement and garden. Many streets use a combination, with fibre running underground along the road and then rising onto a pole for the final span to each house, or vice versa, depending on what infrastructure already exists.
The method chosen is rarely arbitrary. Operators such as Openreach and the various alternative networks prefer to reuse what is already in the ground or on poles, because that avoids new digging, speeds up deployment and limits disruption. Whether your connection arrives overhead or underground therefore usually reflects how your existing copper phone line was routed, since the fibre commonly follows the same path.
How overhead fibre installation works
Overhead delivery uses poles, either existing telegraph poles or, where none are conveniently placed, newly erected ones. A fibre cable is run along the overhead network between poles, and a drop cable is then taken from the nearest pole to a small bracket on the outside of the home. From there it passes through the wall to an optical termination point indoors. Because much of this happens at height and reuses existing pole routes, overhead installation is often the quicker option and typically involves little or no excavation.
The trade-off is visual and practical. Overhead lines are visible, and a new pole may occasionally be needed where the existing network does not reach. Operators carrying out pole and overhead works on or near the public highway must still observe the relevant notice and permit requirements, and a newly sited pole follows the network owner's siting process. For the homeowner, the works are usually completed in a single visit once the wider street build is in place.
How underground fibre installation works
Underground delivery relies on duct: the network of pipes already running beneath many streets and footways. The fibre is installed using blown fibre, a technique in which a thin fibre cable is propelled through the duct by compressed air, allowing it to travel along bends and over distance without a trench being dug for the whole route. From the nearest underground access point, a final length is run to the property, often through an existing duct serving the old copper line.
Difficulties arise when there is no usable duct, or the existing duct is blocked or collapsed. In that case a section of new duct may have to be laid, which means a small excavation in the footway, verge or driveway. Operators aim to keep this minimal and to reinstate surfaces afterwards, and works in the public highway are governed by the permit and reinstatement rules under the New Roads and Street Works Act 1991. A blockage discovered mid-installation is a common reason an underground job takes longer than an overhead one.
Fibre installation methods and the consumer experience
The table compares the two methods from the householder's point of view. The descriptions are general and the actual experience varies by site, but the contrasts hold in most cases.
| Aspect | Overhead (poles) | Underground (duct) |
|---|---|---|
| Digging | Usually none | Possible if duct is blocked or absent |
| Typical speed of install | Often quicker | Quick if duct is clear, slower if not |
| Visibility | Visible drop cable and poles | Hidden underground |
| Weather exposure | Exposed to wind and falling branches | Protected within duct |
| Permissions on private land | May involve a wayleave for a pole | May involve consent to dig |
Neither method changes the speed of the fibre service you ultimately receive; both deliver the same optical connection. The difference is purely in how the cable gets to the wall and what that means for disruption, appearance and resilience during installation.
Disruption, timescales and digging
For most homes the appointment to connect fibre is a single visit lasting a few hours, assuming the wider street network is already built and a clear route exists to the property. Overhead jobs tend to be the most straightforward because they avoid excavation. Underground jobs are equally quick where the existing duct is clear, but can extend across more than one visit if a blockage is found, a new duct section is needed, or street works permits and reinstatement have to be arranged.
If digging is required on the public highway, the operator must follow the notice, permit and reinstatement framework set out under the New Roads and Street Works Act 1991, which is why some street works appear, pause and return for final resurfacing. On private land, such as a long driveway or shared access, the operator may need the landowner's consent to dig or, for a pole, a wayleave. Householders should expect to be asked where indoor equipment can be sited and to give access for the engineer to bring the cable to the chosen termination point.
Why the build matters now
The shift to fibre is happening against the backdrop of the PSTN switch-off, the retirement of the old analogue copper telephone network. Openreach's all-IP migration is set to complete in 2027, after which voice services run over digital, IP-based connections rather than the traditional phone line. Fibre, whether delivered overhead or underground, is central to that transition because it provides the high-capacity, future-ready connection that IP voice and modern broadband depend on.
For households this means the installation method is a short-term consideration, while the connection itself is a long-term one. Whether the fibre arrives on a pole or through a duct, the end result is the same digital service that will carry both broadband and, increasingly, telephone calls. Anyone relying on a telecare alarm or other line-dependent device should tell their provider during the migration so that suitable arrangements, including any battery back-up for resilience, can be put in place.
Frequently Asked Questions
How is fibre optic cable installed?
Fibre is installed either overhead, run between poles and dropped to the property, or underground, blown through existing duct beneath the street. Operators often combine both along a route and prefer to reuse existing poles and ducts to limit disruption. A final short length connects the network to an optical termination point inside the home.
Will Openreach dig up my garden to install fibre?
In many cases no digging is needed because fibre arrives overhead or is blown through existing duct. Excavation only becomes likely if there is no usable duct or an existing one is blocked or collapsed, in which case a small trench may be required. On private land the operator may need your consent before digging.
How long does fibre installation take?
Where the wider street network is built and a clear route exists, the connection appointment is typically a single visit of a few hours. Overhead jobs are usually the quickest. Underground jobs can take longer or need a second visit if a duct blockage, new duct section, or street works permit and reinstatement are involved.
What is blown fibre?
Blown fibre is a technique in which a thin fibre cable is propelled through an underground duct using compressed air. It allows the cable to travel along bends and over distance without digging a trench for the whole route, provided the duct is clear. It is a common method for delivering fibre underground.
Does overhead fibre cause any problems?
Overhead fibre is visible and exposed to weather such as high winds and falling branches, which can occasionally affect the line, and it may require a pole and an associated wayleave on private land. It delivers the same fibre service as an underground connection. Operators carrying out overhead works near the highway must still follow the relevant notice and permit rules.
