KEY POINTS:
What is happening with Vector's powerline undergrounding project in Auckland? It started a few years ago but now there seems to be little evidence of continuing work.
- Peter Grant, Balmoral.
That depends on where you look. The project is still alive and well and, to date, more than 60 sub-projects, or parts of the master plan, have been completed. Another two areas were started in the past month, in Ash St in Avondale, and in Orakei, and work in Horopito St in Mt Eden is 60 per cent completed. Three other projects have already been completed this year, including additional power from Motions Rd to the new Auckland Zoo Hospital.
But there's still lots to do. More than two-thirds of the Vector network is underground, but the remaining 3000km will take some 30 years to bury as a result of budget allocations. Vector spends about $10.5 million annually on undergrounding, in addition to the maintenance still required on poles and lines. Vector aims to carry out one to two major block undergrounding projects every year, as well as smaller jobs.
Where possible, powerline undergrounding is done in co-ordination with the burying of telephone lines and other utilities. Space, time and traffic restrictions also have to be taken into account.
Although undergrounding does not guarantee against future power cuts, outages caused by storms and cars hitting power poles will be greatly reduced.
The cable trenches are generally one metre deep and up to 1.6m wide. They are dug along the centre of main arterial roads so that two lanes of traffic can still flow along each side, and along the side of smaller streets so that traffic still has room to pass.
The cables are made of an aluminium or copper core with plastic insulation. The trenches are then filled with a substance that allows heat to escape, then backfilled with quarry material. A concrete cover is poured to stop future damage from digging and the road material is laid on top.
Projects take from six weeks to six months. The average time of disruption outside a particular property is five weeks.
Vector is the electricity network company in Auckland, Manukau and parts of Papakura. It owns and is responsible for maintaining power lines and cables, and delivers electricity to about 265,000 homes and 38,000 businesses. The publicly-elected Auckland Energy Consumer Trust is the majority shareholder of Vector. Vector also operates as UnitedNetworks in Wellington, and north and west Auckland.
For more information phone 0800 GO UNDERGROUND or (09) 303-0626, or visit www.vectorelectricity.co.nz
