NBN Co has revealed its HFC network accounts for the largest number of unserviceable connections of any fixed-line technology in the rollout.

The network builder last night broke down its reported “not yet ready to connect” (formerly known as service class zero and equivalent) premises number for the first time.

Based on the total number of premises cited - 246,942 - the breakdown is accurate to just after June 22 this year.

NBN Co’s numbers show that 132,691 of these unserviceable premises - 53.7 percent - are in the HFC footprint.

It is likely these are the premises that NBN Co recently admitted were waiting too long “from the time they ordered their service from their retailer to actually being connected to the NBN HFC network".

Chief network engineering officer Peter Ryan said in a blog post earlier this month that “for around half of the premises ordering an NBN HFC service, NBN Co needs to visit the premises and build a new lead-in conduit to connect the coaxial cable into the premises – something that can often be problematic and can cause delays".

At the end of June, NBN Co had declared 758,416 premises ready for service. Knowing the SC20 number (the internal code given to unserviceable HFC connections), about 625,725 of those were capable of a retail connection. The company had 152,786 active users at that time.

While the number of SC20 premises is high, it remains within NBN Co’s serviceability threshold.

NBN Co revealed late last year that “in 2014 [it] introduced new serviceability rules that put a limit on the number of premises that could be at SC0 or equivalent (25 percent)".

“Prior to this, in 2012 and 2013, areas could be declared ready for service with significantly higher proportions of the premises at SC0,” the company said.

The proportion peaked under the leadership of former NBN Co CEO Mike Quigley, when SC0 premises represented 33 percent of the total network footprint at the end of June 2013.

By comparison, the proportion of the total footprint that is unserviceable is now in the single digits percentage-wise.

But the number of SC0 and equivalent premises has risen dramatically in real terms in recent months, apparently due to HFC areas being declared serviceable despite many homes lacking an appropriate lead-in.

On a total network basis, NBN Co is well within its serviceability limits. When only the HFC portion of the network is considered, about 17 percent of all HFC connections are unserviceable, meaning NBN Co remains safe in that regard.

However, the network builder is obviously uncomfortable at the climb in unserviceable HFC premises, and more so the effect that is having on wait times and customer satisfaction in the HFC footprint.

From September 1, it changed the way it declared HFC areas ready for service.

“We have decided to hold back a proportion of these premises in order to better manage consumer expectations on wait times once they’ve placed an order,” Ryan said at the time.

“From 1 September, NBN Co will only release a new HFC footprint to market where there is a lead-in to the premises already in place.”

That should give customers a better idea of when they will able to actually connect to the NBN.

It should also stop HFC from filling up such a large share of the 'not yet ready to connect' numbers.

Other unserviceable techs

In addition to releasing the number of SC20 premises, NBN Co also broke out the number of unserviceable premises that are in the FTTN/B and FTTP footprints.

Of the total 246,942 SC0 or equivalent premises, 106,352 - 43 percent - are either fibre-to-the-node (FTTN) or fibre-to-the-basement (FTTB) users.

The remaining 3.3 percent of unserviceable premises - 7899 in real terms - are in the FTTP footprint.

While the rate of growth in the SC0 and equivalent numbers has slowed in recent weeks, this might be temporary.

NBN Co has forecast the number could top 400,000 this financial year - it currently sits at 278,623 - before backing off to zero by the end of FY20.