NBN: Underground vs overhead cable debate rolls on

As the National Broadband Network (NBN) construction chugs along in Tasmania, debate on the mainland continues as to whether laying the fibre optic cables underground is more advantageous than putting them in existing overhead infrastructure.

Layer 10 founder and NBN lead for the Communications Alliance, Paul Brooks, said the decision on rolling out NBN cabling overhead or underground is a business concern depending on local conditions in each area.

"There's a perception that underground cabling is more reliable, but that's not always true, underground cable can be damaged too," Brooks said.

"It's often cheaper to roll-out cable along the existing power lines, so there's incentive to do that in many areas from a carriers point of view, but if there's existing ducting and pipe work in the ground, then it will go underground. Ultimately it will come down to a cost decision."

Ovum research director, David Kennedy, said although it's expensive to do so, putting fibre optic cables underground does have maintenance advantages.

"That is in fact the case, cable exposed to the weather requires more maintenance and you don't need to be an engineer to realise that," he said.

Brooks said the majority of Tasmania's NBN roll-out is likely to go in overhead cables, due to the existing infrastructure in place by energy provider Aurora, who was also awarded the contract to build the first stage of the NBN.

Peter Downey, chairman of Sydney-based lobby group Cables Downunder, which is opposing the deployment of overhead cables, said the NBN cables must not be built overhead as that will increase running costs and reduce reliability.

“[The NBN] is so important that it must not be built on the cheap as this will increase running costs and reduce reliability,” he said.

After receiving harsh criticism in online forums for presenting unsubstantiated evidence on the issue at the Senate Select Committee, he defended his comments made during his time being questioned by the Committee on October 1.

Downey admitted he floundered at the hearing and that he had expected to see an engineering study presented to the Senate Committee outlining guidelines on how to proceed with the laying of cables.

“They don’t know what they’re doing, they haven’t put down a format and said ‘Here, comment on this.’ So whatever you put up is really hypothetical,” he told Computerworld.

Downey pointed to a 1998 report, written for the then communications minister Richard Alston, titled Putting Cables Underground as proof backing up his claims overhead cables are more costly to maintain than those deployed underground. Research presented in the report estimates the savings in maintenance costs from placing cables underground is $318 per kilometre of cable per year. However, the report does not take into consideration the advancements in technology and changes to the economy since 1998 and no recent evidence was referenced.

Federal communications minister, Senator Stephen Conroy, has said on record that community sensitivities relating to the rolling-out of overhead cabling will be taken into consideration.

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