NBN Pit and Pipe for Subdivisions: What Developers Must Provide

Of all the services in a subdivision, telecommunications is the one developers forget until the end. Water and sewer have Sydney Water breathing down your neck. Electricity has the network operator’s design to get through. The nbn conduit just sits there quietly in the verge, and then someone at council asks for the nbn confirmation letter before they’ll sign the subdivision certificate and the whole thing stops. Here’s how it works and where it sits in the sequence.

Who builds what

The split is simple once you’ve seen it. In a new development the developer builds and pays for the pit and pipe: the underground conduits and pits in the road reserve and the lead-in conduit to each lot. nbn then comes along afterwards and pulls its fibre through the conduits the developer installed, and connects the premises. The developer provides the pipe, nbn provides what goes in it.

That’s the arrangement under the Commonwealth’s telecommunications in new developments policy, and nbn’s own new developments page sets out the process from their side. The key point is that nbn won’t just turn up. You apply, they assess, they tell you what they need, you build it to their specification, they certify it, then they install.

When to apply

Early. nbn’s published guidance is to engage them a minimum of three months before occupation for a small development and a minimum of six months for a larger one, and I’d treat those as absolute floors rather than targets. The application goes through nbn’s online New Developments portal. You need the plan of subdivision, the lot count, the expected timing and the civil design far enough along to show where the road reserve and the verge allocations are.

What comes back is an agreement with nbn setting out what infrastructure you’re providing, to what standard, and what nbn will do once it’s built. Don’t start the civil works before this is in hand, because the pit and pipe has to go in the ground at the same time as everything else, and if nbn’s requirements change your pit locations you want to know before the kerb is poured.

What “pit and pipe” actually means

Physically, it’s:

• Main conduits running along the verge, usually in a shared services trench with power and sometimes water, following nbn’s alignment rules.
• Pits at intervals along the run, at changes of direction, at road crossings and at the points where the lead-ins branch off. Pit sizes and types are nbn’s call.
• Road crossings in conduit under the pavement, installed before the road base goes down.
• Lead-in conduits from the pit to each lot, terminating at the property boundary with a cap and a marker so the builder can find them later.
• Draw ropes in everything so nbn can haul the fibre.

The specification for all of this comes from nbn’s design guidelines for new developments (their develop or plan with the nbn section is the starting point), and the design has to be done by someone who knows those guidelines. Our group company Pit and Pipe does the nbn design and certification work for the subdivisions we do the civil engineering on, and the reason we keep it in the family is that the pit and pipe has to be coordinated with the rest of the civil drawings rather than drawn over the top of them afterwards.

Where it fits in the civil design

This is my part. The nbn conduit lives in the verge along with the water main, the sewer (sometimes), the electricity conduits, the gas, and the stormwater pipes and pits. There’s a standard allocation of who gets which strip of the verge, and the shared trench for power and communications generally has its own set-out. The civil engineering design for the subdivision has to reserve those alignments, and the things that go wrong are always clashes.

The clashes I see most:

• Stormwater pits in the comms alignment. A kerb inlet pit is a big concrete box, and if it’s sitting where the nbn pit wants to be, one of them moves. Sort this on the drawing.
• Driveways over pits. Nobody knows where the driveways will be on a greenfield lot until the houses are designed, but an nbn pit in the middle of a likely driveway location will be run over by every concrete truck on the street. Put pits at lot boundaries where the driveways aren’t.
• Road crossings after the pavement. If the conduit crossing is forgotten and the road is built, someone is either saw-cutting the new pavement or directional drilling under it. Both cost money and both annoy the council. Crossings go in with the subgrade.
• Depth of cover. The conduits have a minimum cover, and where the pavement design or the verge grading is changed late, that cover can disappear. Check it on the long sections.
• Retaining walls and batters. On a sloping subdivision the verge might be on a batter or behind a wall, and the conduit alignment has to survive that. This is a coordination job between the civil engineer, the pit and pipe designer and the retaining wall designer.

Construction and certification

The pit and pipe is built by the civil contractor as part of the subdivision works, usually by a subcontractor who does comms installs and knows nbn’s requirements. When it’s done, nbn requires certification that it was built to their specification, with as-built drawings showing what’s in the ground. This is a proper certification, not a letter saying “done”, and it’s usually issued by the pit and pipe designer or an nbn-accredited certifier after inspection.

That certification is what unlocks two things: nbn accepting the infrastructure so they can install their network, and the council’s subdivision certificate.

The council’s interest

Almost every subdivision consent in Sydney has a condition requiring the developer to provide evidence, before the subdivision certificate is issued, that telecommunications infrastructure has been provided to the lots. In practice that means a letter or confirmation from nbn that the pit and pipe has been completed and accepted. The council isn’t checking your conduit. They just want the confirmation. But if you haven’t applied to nbn in time, or the certification is held up because a pit was installed wrong, the subdivision certificate waits and the lot sales wait with it.

It’s the same category as the Sydney Water Section 73 certificate and the electricity provider’s confirmation: a piece of paper from an authority that you can’t get quickly if you’ve left it late.

What happens on the lots afterwards

Once the lots are sold, each builder connects the house to the lead-in conduit at the boundary and runs their own conduit to the premises. If the lead-in wasn’t capped and marked, or was crushed by the excavator during the house build, the builder is digging in the verge looking for it. It’s worth putting the lead-in locations on the as-built drawings handed to purchasers, because the question always comes back to the developer.

A sequence that works

1. Plan of subdivision and civil concept done. Lodge the nbn New Developments application at this point.
2. nbn agreement received. Pit and pipe design prepared against the civil drawings, verge allocations checked, clashes resolved.
3. Pit and pipe drawings included in the subdivision works certificate package with the roads, drainage and utilities.
4. Conduits and crossings installed with the subgrade and the shared trench. Pits set at final verge level.
5. Inspection and certification. As-builts prepared.
6. nbn accepts. Confirmation obtained for the subdivision certificate.

None of that is hard. It’s just a lot of it has to happen early, and the developer who applies to nbn after the roads are sealed is the developer who ends up saw-cutting a new road to put a conduit under it.

If you’re planning a subdivision, put the nbn application on the same list as the Section 73 and the electricity design, and do them all in the first month. The conduit is cheap. The delay isn’t.