A power surge forced Yale’s physical plant on Tower Parkway to shut down Sunday morning, temporarily leaving most of campus without heat or hot water.

The hour-long outage, which affected nearly all of central campus and Science Hill, occurred when external electricity lines leading into the plant malfunctioned. Sunday’s blackout was the second time in the past year that such a glitch has shut down the plant, prompting concerns among Facilities officials that a faulty external power distribution system may pose a risk to Yale’s heat supply.

The shutdown was one of a number of apparently unrelated heating and cooling problems occurring over the last week. The other incidents included a loss of hot water in Jonathan Edwards College Monday morning and a water leak in the Becton Engineering and Applied Science Center throughout the day Monday.

Director of Utilities Joseph Nadolny said Sunday’s error occurred when a power distribution system intended to supply backup power to the plant malfunctioned, triggering an automatic shutdown designed to prevent damage to the lines. Yale officials said they will hold discussions this week with United Illuminating, the New Haven company that owns the distribution system, to prevent potentially more serious outages. If the plant had shut down in colder weather, frozen pipes might have ruptured and caused severe damage to school facilities, Nadolny said.

“Normally [the company is] supposed to be backing us up, but the last two times we had to shut down it was because they had problems in their system,” he said. “If it had been at the worst point, we could have had major problems with our steam coils freezing and damage to equipment and buildings.”

Officials said the power disruption was likely due to a thunderstorm, but they have not verified the details of the incident or confirmed that it did not cause any damage to University buildings. Since such line failures are expected to happen only once every several years, administrators have begun to doubt the reliability of the backup power system, Associate Vice President for Facilities Operations John Bollier said.

“It’s happened twice in the last year, and that’s more frequent than we’d like it to happen, and we’ll be talking to UI about it,” Bollier said.

United Illuminating has a monopoly on the local power grid, so the University’s only option is to work with the company to improve its system, Nadolny said. The company may need to upgrade its power lines, he said, or Yale may need to adjust its security sensors to make them less sensitive to fluctuations in the grid.

Representatives for United Illuminating were unavailable for comment Monday night.

The plant shutdown was one of a series of apparently unrelated problems with Yale’s piping system this week. Cold weather caused a coil to rupture in the Becton Center on Monday, depriving the building of chilled water used for temperature control in some experiments. Chemistry professor Gary Haller said he is not aware of any disruption to current experiments or larger damage to the facility.

In an unrelated incident, Jonathan Edwards College lost hot water again Monday morning, though JE and University officials were unable to confirm the cause.

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