A campus link fails differently from an office run. The glass is almost never the problem. It is water sitting in a duct, a bond nobody made at the entrance, or an aerial span tensioned for a mild winter that we do not get here.
Outside plant is the fiber between buildings: across a campus, an industrial park, a municipal yard or a plant site. Different cable, different route, different rules from anything inside the walls, and a job you only want to do once.
Choosing the route before choosing the cable
Almost every quote we lose on price was priced against a route that did not exist. Someone measured building to building on a site plan, called it 400 metres, and nobody checked whether the duct between them was free.
We survey the route first. If there is existing duct with a spare way, the job is a pull and two splice trays. If there is not, the cost moves by a factor that has nothing to do with the fiber.
| Route | Relative cost | Lead time | Main risk | When it wins |
|---|---|---|---|---|
| Existing duct | 1.0× | Days | Duct is blocked or already full | Almost always. Prove the duct first, everything else is a fallback |
| Aerial, existing poles | 1.5 to 3× | Weeks, permits | Pole attachment approval and make-ready | Long spans on land you do not own |
| New duct, bored | 6 to 12× | Weeks | Unknown services underground | You want a route you can re-pull in five years |
| Direct burial | 4 to 8× | Weeks | No second chance without digging again | Short runs on your own land, no future adds expected |
Cable that survives an Ontario winter
Outside plant cable is built around keeping water away from the glass and surviving a freeze-thaw cycle every spring. Indoor cable in a duct will fail, and it will fail in February.
| Construction | Where it goes | Rodent | Typical range | Watch for |
|---|---|---|---|---|
| Loose tube, gel filled | Duct, direct burial | No | −40 to +70 °C | Messy to prep. Budget time at every splice |
| Loose tube, dry block | Duct, riser transition | No | −40 to +70 °C | Cleaner prep, now the default for most jobs |
| Armoured, corrugated steel | Direct burial | Yes | −40 to +70 °C | Conductive. It has to be bonded at entry |
| ADSS | Aerial, self supporting | No | −40 to +70 °C | All dielectric, no bonding. Span and sag must be engineered |
| Figure 8 | Aerial, short spans | No | −40 to +70 °C | Messenger is steel, so it is conductive and needs bonding |
The building entrance is where jobs fail inspection
This is the part specifications get wrong most often, usually because they were copied from a US document.
In Ontario the work falls under the Canadian Electrical Code, Section 56. Cable inside the building has to be a type approved for that use, and where a cable has conductive non-current-carrying members, armour or a steel messenger, those members have to be bonded to ground as close as possible to the point the cable enters the building.
The 15 metre or 50 foot allowance people quote is NEC 770.48, which is the American code. It is a sensible design target and we build to it anyway, but it is not the rule your inspector is working from. Where a spec cites it, we flag it and confirm the approach with the authority having jurisdiction before anything gets pulled.
What the loss budget actually looks like
Campus distances worry people more than they should. Singlemode has room to spare over the distances a campus involves. Here is a link we would call typical, worked through end to end.
| Element | Count | Allowance | Loss |
|---|---|---|---|
| Fiber, OS2 at 1310 nm | 0.9 km | 0.35 dB/km | 0.32 dB |
| Fusion splices | 2 | 0.05 dB each, field | 0.10 dB |
| Connector pairs | 2 | 0.25 dB each, field | 0.50 dB |
| Measured link loss | — | — | 0.92 dB |
| 10GBASE-LR budget | — | — | 6.2 dB |
| Headroom | — | — | 5.3 dB |
Five decibels of headroom means the link still passes after a repair splice, a dirty connector cleaned badly, and a future patch panel. That is the point of the exercise. A link with no headroom passes on the day and fails the first time anyone touches it.
What you get when we hand it over
- OTDR traces from both ends, at 1310 and 1550 nm, with the files, not just a pass mark.
- Insertion loss results against the budget we set at design.
- Splice loss records per fusion, both directions averaged.
- As-built route drawings, including depth and duct occupancy where we added any.
- Both ends labelled to a scheme you can still read in five years.