NBN Co claims it drastically over-estimated the amount it has spent on new copper cabling in the fibre-to-the-node rollout, slashing its spend by half.

The company has faced criticism since it emerged back in 2015 that it was spending millions to buy new copper cabling for the build.

It has previously said most of the new cabling is for cross-connects between existing pillars and FTTN cabinets, as well as for remediation work on the existing copper network.

However, some of the new copper cabling is being rolled out in new housing estates, which - after a policy change - no longer need to be exclusively cabled using fibre.

While it has been spending on new copper, NBN Co now claims the bill is far less than it has previously reported.

The company last pegged its spending on “copper materials” at $177.1 million as at June 20.

But NBN Co now claims this was an “error”.

The estimate “in relation to the value spent on new copper cable as at 20 June 2017 was in error, as the data extract to ascertain the value had included materials other than copper cable,” NBN Co said overnight.

“The correct value spent on new copper cable as at 20 June 2017 was $89.5 million.”

That would mean NBN Co has spent only half as much on copper cabling as it has previously stated.

Its spend has since climbed to $96.8 million - a figure which is current to October 22.

FTTC’s G.fast upgrade

It was also revealed overnight that the upgrade path for many fibre-to-the-curb (FTTC) users to G.Fast technology is not as simple as a soft upgrade to network equipment.

G.fast has previously been touted by NBN Co as an “upgrade path” technology for fibre-to-the-curb (FTTC) and fibre-to-the-basement (FTTB) users, pushing their theoretical speeds above 100Mbps.

NBN Co has said it will likely limit G.Fast to commercial end users in the FTTC/B footprints. But there could be technical as well as business reasons to do so.

Last night NBN Co said distribution point units (DPUs) - which connect homes to the NBN - that are deployed as part of the initial FTTC rollout will support VDSL only.

“Future deployment of DPUs will support G.Fast,” it said.

The network builder said it “intends to include G.Fast capable DPUs as part of the FTTC rollout” but it did not say how many nor where.