Quick answer: an engineer runs a fibre cable from a pole or underground to a small box on your outside wall, then inside to a white box called an ONT, which connects to your router. Openreach says most installations take between one and four hours. Someone over 18 must be home for the whole appointment.
On the day, step by step
The engineer calls ahead
They'll phone before they arrive.
You agree the route together
You'll agree where the cable runs and where any hole is drilled. If drilling or digging is needed, you'll sign a "permission to work" form.
Fibre reaches your house
The cable comes from a nearby pole or underground to a small box on an outside wall.
The ONT goes in
A cable runs inside to the ONT, a small white box that plugs into the mains. Your router connects to it.
Testing and tidying
The engineer checks the connection works and tidies up before leaving.
How to get ready
- Someone over 18 must be in for the whole appointment, Openreach says.
- Renting? Get your landlord's permission for drilling before the day.
- Pick a spot for the ONT and router near a double power socket, somewhere central for good Wi-Fi.
- Have a line-based alarm or health pendant? Tell your provider before the appointment.
- Clear the way to where the cable will come in, inside and out.
How long does it take?
Openreach says most installations take between one and four hours, though its checklist suggests allowing around four. More complex jobs, such as when new underground cable is needed, may need a second visit.
After the install
Your provider supplies the router and sets up your service. Ask your provider whether the router arrives in the post or comes with the engineer, and whether your old broadband stays on until the switch. Full fibre is also ready for the end of old copper phone lines, as home phone services now run over broadband.
Comparing providers? Independent networks such as Zzoomm and Highland Broadband build their own full fibre, with their own installation teams, so the steps may differ slightly.
Time for faster broadband?
Full fibre plans with matching upload speeds and free installation, from £22 a month.
FAQs
Do I need to be home for a full fibre installation?
Yes. Openreach says someone over 18 who can make decisions about the work must be home for the whole appointment.
Will they need to drill a hole?
Usually, yes, a small hole to bring the cable inside. You agree the spot with the engineer first and sign a permission form.
How long does full fibre take to install?
Openreach says most installations take between one and four hours. Complex jobs can need a second visit.
What is an ONT?
An optical network terminal: a small white box inside your home where the fibre cable ends. Your router plugs into it.
Steps checked on 2 November 2026 against official help pages: Openreach: installation checklist · Openreach: how full fibre is installed. Menu names can vary slightly by phone model and software version.