Hazard fears over power and gas lines

File photo / Hawke's Bay Today

Auckland Transport fears power and gas lines are running too close together across one of its busiest traffic routes, and constitute a hazard.

The council-controlled organisation has, in a submission to the Government, claimed there is a risk of induced electricity voltages from overhead transmission lines on gas and water pipes under Wolverton St in New Lynn.

That "poses a hazard", says the submission, which recommends changes to a draft national code of practice for allowing utility companies access to transport corridors.

Induced voltages are the transference of electrical charges from power lines to other objects, usually metallic, through a magnetic field.

Two sets of transmission lines - one of 110,000 volts and the other of 220,000 volts - carry electricity over Wolverton St to Northland.

But national electricity grid operator Transpower denies there is a hazard, saying safety is paramount in the design, construction and maintenance of its assets.

"This includes taking into consideration how our assets interact with other utilities and the impact they have on the public," said spokeswoman Rebecca Williams.

Neither Auckland Transport nor Transpower was able to say yesterday what distance separates the power and gas lines, which have co-existed since 1970.

But Ms Williams insisted an electrical code of practice controlling separation distances would have been adhered to, and that neither neighbouring properties nor the 33,380 vehicles which use Wolverton St daily were at risk.

Auckland Transport raised the issue to support a bid for greater control by roading authorities over where utility lines are placed through their corridors.

Spokeswoman Sharon Hunter said the organisation was "comfortable" with Transpower's reassurance, despite having raised the alarm.

Auckland Transport's submission also seeks powers to prevent electricity companies and other service providers from digging up its roads for five years after major construction work.

That follows controversy over extended roadworks for several summer months in Quay St, just two years after similar disruption to traffic along one of the city's busiest routes.

Power supply company Vector was involved in both cases, although its latest activities in installing new cables and ducting were combined with a $2.5 million Auckland Transport project to rebuild the road.

That was in line with new legislation aimed at encouraging greater co-operation between road controlling authorities and utility companies, for which the proposed national code of practice is due to become mandatory by September.

The Auckland Transport submission says it spends about $1.2 billion a year on maintaining, operating and improving its network while dealing with more than 15,000 corridor access requests annually from utility companies. It says a single utility trench can reduce the life of a road by up to 34 per cent, against a normal expectancy of 25 to 40 years.