Nova Scotia Power is installing four new undersea power cables to Brier Island.
The $2.2 million dollar project will replace the three cables installed in 1997.
Nova Scotia Power spokesperson David Rodenhiser says one of those cables had failed causing an outage in 2010.
The other two were deteriorating due to the heavy currents in Grand Passage.
The 1997 cables were installed to replace three cables that failed at once requiring Nova Scotia Power to set up a temporary generator on the Island.
After the 2010 outage, NSP crews changed the configuration of a bank of transformers on the Island to convert two-phase power to three-phase power for the bigger power users who are running motors or compressors for example.
The new cables means NSPi will once again be delivering three-phase power to the island.
Rodenhiser says each of the four new cables is 1.2 km in length – the fourth he calls a ‘hot spare’.
“We only need three cables but the hot spare gives us some extra reliability,” he said by phone from Halifax.
Crews are burying the cable ends and running them through piping to protect them from the constant tidal movement.
“This will be a more robust solution,” he says. “We are installing an articulating mechanical collar on either end of the crossing to provide shallow water abrasion and impact protection to the submarine cables.”
Nova Scotia Power had looked at an overhead option.
Rodenhiser says it would have cost more and had a couple of drawbacks.
“Overhead wires would require very high towers in order to maintain the minimum navigable waters clearance requirement of 30 metres,” he says. “As well, it would have taken longer to complete because we would have needed a public consultation process, and to negotiate and secure land easements and permits.”
Nova Scotia Power engineers designed the solution, and are overseeing and managing the process.
IT International Telecom of Halifax is doing the actual installation with a specialized barge and two tugs.
As of Thursday, Jan. 17, workers had installed three of the cables and were awaiting good weather to put the fourth in place.
“We’re hopeful for Wednesday (Jan. 23),” says Rodenhiser. “Wind conditions are the most significant consideration.”