Pit and pipe design for multi dwelling unit developments
For apartment buildings, townhouse sites and other developments with multiple dwellings on one lot. We design the lead-in from the street, the pits and conduits across common property, and the pathway to each dwelling.
Reviewed 14 October 2026 against NBN-TE-CTO-194 Revision 13.0 and NBN-TE-CTO-284 Revision 16.0
In short: an MDU design gets NBN fibre from the street network into a building or across shared land to every dwelling. For a vertical MDU that means a P50 or P100 lead-in to the building and space for NBN equipment inside it. For townhouses on common property it means a small internal pit and conduit network. We prepare both to NBN's current standards, from $120 per dwelling, within two weeks of receiving complete CAD plans.
What counts as an MDU
NBN defines a multi dwelling unit as a building or site with multiple dwellings within a single lot. In practice there are three common types, and each has its own rules.
Vertical MDU
An apartment block, mixed-use building or office block where the dwellings sit above and beside each other inside one structure. NBN's MDU building standard, NBN-TE-CTO-284, covers the lead-in, the communications room, risers and the pathway to each unit.
Horizontal MDU (HMDU)
Townhouses or villas where the pit and pipe sits on land that will be owned by a body corporate. Instead of transferring the works to NBN, the developer grants NBN a licence for exclusive use of them. NBN publishes a separate booklet for HMDU builds.
Super lots
A large lot that will later hold several premises. The internal network depends on the number of premises: three or fewer get individual P20 lead-ins across common property, 4 to 24 get an internal P50 pit and conduit network, and 25 or more get a P100 local network with P50 laterals. Pits and conduits must not be placed in, or cross, the individual titles inside a super lot.
Not sure which type your site is? Our SDU or MDU guide walks through it, or tell us what you have and we will confirm.
The lead-in to the building
2 to 60 premises: one white P50 lead-in conduit.
More than 60 premises: one white P100, or two white P50 lead-in conduits.
The service drop to a vertical MDU follows the same split: P50 up to 60 internal premises, P100 above 60.
All conduits meet AS/NZS 1477 and carry a draw string.
Inside the building, the lead-in runs to the first termination point, usually the communications room or a riser, through an accessible cable tray or a single P50 with draw string.
Space for NBN equipment
NBN's MDU standard asks the developer to provide space for fibre equipment. The minimum allocation is 1 m by 1 m in the communications room and a 500 mm by 500 mm footprint per floor in the riser, each with equipment between 400 mm and 1,800 mm above floor level and 1,000 mm of clear access in front. Small MDUs can use an external enclosure as the building entry point instead, sized at least 600 by 600 by 300 mm for up to four premises and 800 by 800 by 300 mm above that. Getting this space into the architectural drawings early avoids late redesign.
The pathway to each unit
Each dwelling needs a pathway from the riser to its network termination device. The usual option is a dedicated conduit, minimum P20, to each unit, with no more than 50 m between pull points and no more than the equivalent of three 90 degree bends. A shared P50 pathway with access panels is the alternative. Inside each unit, NBN sets the height and location of the termination device, with external walls, roof cavities and damp areas ruled out.
What the design covers
- Pit locations and conduit routes from the street network to the building or common property
- Lead-in conduit size and quantity for the number of premises
- The internal pit and conduit network for horizontal MDUs and super lots
- Building entry point, communications room and riser locations, marked on your plans
- Existing roads, poles, transformers and telecommunications pits around the site
- A design set ready to upload to the nbn New Developments portal
See what's in a design package for the full deliverable.
What we need to start
- Site address and state or territory
- Number of dwellings and the stage of the development
- CAD (DWG) site plan, plus floor plans for vertical MDUs
- Where common property and individual titles will sit
- Your NBN application reference, if you have one
- Dial Before You Dig or site survey results, if you have them
Price
From $120 per dwelling, with lower rates as the project grows. A 60 unit building is $6,015. See the price guide and calculator.
MDU design questions
What size lead-in does an apartment building need?
Under NBN's MDU standard, a building with 2 to 60 premises needs one P50 lead-in conduit. Above 60 premises it needs one P100 or two P50 conduits.
How much space does NBN need in the building?
At least 1 m by 1 m in the communications room and a 500 mm by 500 mm footprint per floor in the riser, with 1,000 mm of clear access in front.
Are townhouses an SDU or an MDU?
If each townhouse has its own title on a public road, it is usually treated like an SDU. If the townhouses share common property owned by a body corporate, it is a horizontal MDU.
Who owns the pit and pipe in a horizontal MDU?
For most developments the developer transfers the works to NBN. For a horizontal MDU the developer instead grants NBN a licence for exclusive use of the works.