If your full fibre broadband has gone down after garden work, or an installer has mentioned splicing on a quote, you are probably wondering what it actually involves. Splicing is simply the process of permanently joining two optical fibres so light passes through with almost no loss. Here is what it means in practice, and the situations where it is genuinely the right fix.
A fibre optic cable carries your broadband as pulses of light through strands of glass thinner than a human hair, around 125 microns across. Unlike copper, you cannot twist two ends together or fit a connector block. The glass has to be cleaved, aligned and joined so precisely that the light barely notices the join.
Fusion splicing does this with an electric arc that melts the two glass ends together. Done properly, a fusion splice loses around 0.02 to 0.05 dB of signal, which is effectively nothing. The joint is then protected with a heat shrink sleeve and stored in a splice tray or closure so it cannot be bent or strained.
There is a second method, mechanical splicing, where the fibres are aligned inside a small precision clip with a gel that matches the optical properties of the glass. It needs less equipment and works as a quick fix, but it typically loses ten times more signal than a fusion splice and costs more per joint in parts.
For anything permanent, fusion is the standard. Mechanical splices are best treated as a temporary repair to get you back online while a proper fix is arranged, for example after a cable is cut on a Friday evening.
The most common call-out we see across Edinburgh, the Lothians and North England is a severed drop cable: a fence post hole, a digger in the garden, or a hedge trimmer catching the line where it runs along a wall. If the glass is broken, the cable must be spliced or replaced. No amount of router restarting will help, and a visibly kinked or crushed section usually needs cutting out too.
You also need splicing when extending fibre to an outbuilding, garden office or a second building on a farm or business site, when connecting a new cable run to existing infrastructure, or when a landlord is bringing full fibre into a tenement or block and each flat needs joining to the riser cable. Older stone buildings common in Edinburgh often force tight, awkward routes, and splicing lets an engineer join shorter manageable sections rather than fighting one long pull.
An engineer will first test the line with an OTDR, a device that sends light down the fibre and reports how far away the break is, often to within a metre. That matters because the visible damage is not always where the glass has actually fractured. They then strip and clean the cable, cleave each fibre to a mirror-flat end, fuse the ends in the splicing machine and test the joint before sealing everything in a weatherproof closure.
A single straightforward repair usually takes one to two hours on site. If your broadband provider owns the damaged section, the repair is normally their responsibility and often free, so check with them first. Splicing you arrange privately typically applies to cabling on your own property, and costs depend on access, cable type and how much needs replacing rather than a flat fee, so expect a survey or photos to be requested before a firm price is given.
Honestly, no, and not because the work is secret knowledge. A decent fusion splicer costs several thousand pounds, and cheap unbranded units produce lossy joints that cause intermittent faults which are miserable to trace later. Bare fibre ends are also genuinely hazardous: tiny glass shards can embed in skin, and you should never look into a live fibre because the infrared light is invisible but can damage your eye.
The sensible DIY line is preparation: safely expose the damaged area, photograph it, note where the cable enters the property, and keep pets and children away from any broken ends. That saves the engineer time and can shorten the visit.
For privately arranged work, a straightforward single repair typically falls somewhere in the low hundreds of pounds including the call-out, though it depends on access, cable type and how much cable needs replacing. If the damaged section belongs to your broadband provider, report it to them first as the repair is usually theirs to fix.
A properly made fusion splice, sealed in a protective closure, should last as long as the cable itself, typically 25 years or more. Failures almost always come from poor sealing or strain on the cable rather than the joint.
Usually yes. Once the joint is fused and tested, the light path is restored and your router should reconnect within minutes, with no need for the provider to reactivate anything, provided no other equipment was damaged.
Send Scott the details and we'll get a realistic price back to you, usually the same working day.
Tell us about the job. A photo of the cabinet or a rough cable count is plenty to get a price started.