Stop us if you've heard this one before: the federal government has managed to alienate important stakeholders in the telecommunications industry, and they're pushing back.

This time, its the companies that own retail electricity infrastructure. As part of the multi-technology model that mandated an end to the fibre-to-the-premises rollout, the government also mandated the transfer of HFC network assets to nbn TM .

Since part of the push-back from the electricity networks is about cost, it looks like the Patented Malcolm Turnbull NBN Forward Cost Estimator will need another workout.

To make sure the network could support future upgrades like DOCSIS 3.1, the Department of Communications also decided HFC networks would need thicker overhead cables, and that's what the electricity networks don't like.

The Department put forward changes to the definition of “low impact” telecommunications facilities so that nbn TM would be able to install cables for the fibre part of the HFC network that are 48 mm instead of what's allowed at the moment – 30 mm.

It can't handle the strain, captain!

The 60 per cent increase has electricity networks up in arms for several reasons, among them various safety issues, and the number of poles they'd have to replace if the new cables are too heavy.

As Endeavour Energy notes in its submission to the Department, the heavier HFC cable has a much higher breaking strain (risking a pole breaking if the cable is snagged by a truck), and the extra thickness also increases the wind load on the poles.

The likelihood that poles will have to be replaced to cope is noted by West Australia's Office of Energy Safety: “We understand the cost of a like-for-like pole replacement is in the order of $10,000 per pole, depending upon pole size, location and conductor/equipment configurations.”

And that excludes considerations like engineering design, disruption to service and the like.

Queensland's Ergon Energy notes that the charges it levied on Telstra and Optus were based on the 30 mm cables, and reckons its fees would have to rise for the thicker cables.

As well as echoing the certainty that poles will have to be replaced to cope with the new approach, Ergon also notes that the new design will demand more nodes be attached to its poles, and these aren't covered by its current agreement with nbn TM .

Similar concerns are raised by WA's Horizon Power, Ausgrid, and Essential Energy.

Another concern is that at 48 mm, the cables can be mistaken for electrical conductors, with Endeavour Energy attributing a fatality in 2013.

It should be noted that in the relatively-rare examples of PSTN cables being strung above ground, the MTM proposal seeks an increase in diameter from 30 mm to 40 mm, with similar load impacts on the network.

The consultation is here. ®