Just in time for a heat wave, Martha’s Vineyard is relying partially on backup generators for electricity after an electric cable failed last week.

NStar spokesperson Michael Durand said Tuesday that electricity to the Island is being provided via two underwater cables and up to 15 temporary generators on Island.

Power is normally transmitted through four underwater cables, Mr. Durand said, but one cable came out of service about a year and a half ago and is not slated to be reinstalled until sometime next year. The second cable failed on Friday along the Falmouth-Vineyard shipping lane, he said. That cable is expected to remain out of service until next month.

The location of the failure occurred in an area where the cable has been snagged by boats and barges in the past, which was a likely contributing factor to its disruption, said Mr. Durand.

NStar is now making arrangements to repair the cable, which must be lifted out of the water onto a barge.

The news comes as NStar is expecting to see record high electricity use in the New England area. But even with the reliance on generators for power, Mr. Durand said NStar is not “anticipating any issues.”

“Weather like this, regardless of generators and cables in service, increases the likelihood that a fuse on a line may blow and we may have to make a repair,” Mr. Durand said. “That’s not to say that sporadic outages will not occur, and that the weather increases the likelihood that may happen. But in terms of big picture and getting electricity to customers on the Vineyard, we have that in place.”

The use of generators on the Island is a standard seasonal practice, regardless of repair work, Mr. Durand said. NStar typically brings extra generators to the Vineyard during the summer to meet increased demand and supplement the cables, he said. Prior to this summer, NStar brought over eight temporary units to be used if necessary.

Due to the cable failure last week, the utility company brought over an additional seven units.

Mr. Durand said not all of the generators are in use at this time.

The 15 generators provide roughly 27 megawatts of additional capacity and are placed in “strategic locations” across the Vineyard, Mr. Durand said.

“They are hooked up in areas that, based on our analyses, will benefit from them the most,” he said. “The generators operate independently from each other and at this point we have not had to run all of them at once.”

“The most important consideration is to provide reliable electrical service.”

At the Edgartown selectmen’s weekly meeting on Monday, town administrator Pamela Dolby told the selectmen that NStar is trying to find a place for two of the generators in the Ocean Heights area of town.

“And we’re expecting a heat wave this week so let’s all hope the generators work really well,” she said.

The arrival of temporary generators comes in the wake of controversial utility poles being installed on the Island. The new underwater cable is part of a longer-term plan to bring more reliable service to the Island. The poles, which can handle a higher electricity load, need to be in place prior to installing the cable, Mr. Durand said. The land use planning committee of the Martha’s Vineyard Commission recommended Monday that the matter of new poles be referred to the commission as a development of regional impact.