Australian data center provider Global Switch has attributed Thursday morning’s power interruption that brought down a number of customers’ servers to a contractor who mistakenly activated a system that shuts down UPS units in case of a fire.

Without naming the contractor, Global Switch managing director Damon Reid told Computerworld Australia that a group of UPS systems at the company’s Sydney data center was shut down as a result of the fire-trip activation, cutting off power to a “very small” number of customers.

The incident affected equipment that was connected to only one of the facility’s two power feeds, and Reid said the provider did not breach any service level agreements as a result. “A very small number of customers had a loss of power on one feed,” Reid told itnews. “Wherever possible, clients should take advantage of two feeds of power.”

Companies that were affected by the outage included PacNet, HarbourMSP, Exigent and Servers Australia, according to itnews.

PacNet Australia CEO Deborah Homewood said the telecom’s core network was not affected, but the incident did have an impact on “some edge services.”

The power feed was shut down around 10:20 am. Reed said the feed and the affected UPS array were restored within one hour.

Global Switch owns and operates more than 3m sq ft of data center space across seven locations in Asia-Pacific and Europe. As DatacenterDynamics reported earlier this week, the company has recently kicked off a US$1.59bn expansion of its data center footprint in the two regions.

Global Switch is planning to expand existing facilities or build new data centers in Paris, Amsterdam, London, Sydney, Singapore and Hong Kong.