A leaked internal NBN document has revealed the network builder will deploy thinner fibre optic cables throughout its network after finding the cables significantly reduced construction costs.
The second leaked document to come out of NBN Co this week reveals the network builder tested a new MT-LFN (multi-technology local fibre network) in two sites in Victoria from mid 2014 to the end of last year.
The MT-LFN uses thinner optical fibres - similar in shape to Ethernet cables - instead of the thicker, green fibre used to date, to address expensive construction problems with duct blockages.
The MT-LFN also means NBN Co can ditch fibre distribution hubs and therefore large pits and street cabinets by using smaller multi-ports, the thinner cables, and more flexible joints.
The trials found the thinner cables lowered the cost of fibre deployment by half, from around $1200 to $600, due to their ability to more easily go down ducts and therefore avoid civil works.
The thinner cables contain around 30 percent of the fibres of the Type2 cables, and are around 35 percent of the thickness.
Currently FTTP connections cost NBN Co $4419 per premise, compared to $2300 per FTTN premise, it revealed at its last financial results briefing.
NBN Co is now planning to expand its use of the thinner cable throughout its multi-technology network.
It is understood the thinner cables will predominantly be used in FTTB connections to multi-dwelling units, for fibre on demand rollouts, FTTP deployments, and in areas where duct blockages are a problem or where ducts have not been upgraded in some time.
The thicker cables will still be used for larger ducts.
It is unclear how much of the thicker fibre NBN has in stock from fibre supplier Corning.
An NBN Co spokesperson said it was a matter of public record that FTTP was the most expensive and difficult technology in the MTM NBN to build.
"... so naturally we would always look at ways to reduce cost and time. This would be expected of any company, especially one spending taxpayers' money," they said.
"It’s also worth remembering the backbone of the whole network is fibre, regardless of access technology."
Shadow Communications Minister Jason Clare said the leaked document indicated the cost of deploying FTTP was going down, and argued the government had "got it wrong" on canning Labor's all-fibre network for a multi-technology mix approach.
The document is the second to leak from inside the network builder this week.
A separate internal document revealed NBN was running behind on its targets for FTTN deployments, having only completed fibre connections to 29,005 FTTN premises despite an internal target of 94,273 as at February 19.
It also revealed final designs had only been approved for 661,665 premises despite a target of over 1.4 million.
Additionally, the cost per connection for each FTTN premise had reached $1366, the report revealed, against a targeted price of $1114.
NBN denied it was running behind and said it had proven "repeatedly" that it can "effectively monitor risks and manage those risks".