ESB says power cut not due to lightning

ESB HAS ruled out lightning as the cause of a power cut which disrupted data centres used by internet giants Microsoft and Amazon.

The ESB yesterday said that partial supply disruption lasted up to five hours, rather than one hour as initially indicated.

A power cut at 6.15pm on Sunday saw Amazon and Microsoft’s cloud computing services based at Citywest disrupted.

The ESB said that the problem was the failure of a transformer in its Citywest substation.

“The cause of this failure is still being investigated at this time, but our initial assessment of lightning as the cause has now been ruled out,” a statement from ESB Networks said.

Amazon appeared to be badly affected by the outage, with systems inoperable for several hours on Sunday night. Amazon was still working to restore all customer data yesterday, according to updates on its website.

On Monday, the ESB said power was disrupted in the area for about an hour. However yesterday it confirmed that there was a partial loss of supply for a further four hours.

Yesterday the ESB confirmed that Amazon was one of about 100 customers affected by the ongoing service interruption.

“This initial supply disruption lasted for approximately one hour as ESB Networks worked to restore supply. There was an ongoing partial outage in the area until 11pm. The interruption affected about 100 customers in the Citywest area, including Amazon and a number of other data centres.”

A second Amazon data centre in south Dublin experienced a “voltage dip which lasted for less than one second”, the ESB said yesterday. However, this data centre was not directly affected by the power cut.

Microsoft’s service was also knocked out but, according to a Twitter update, was back within hours.

Cloud computing involves running software remotely in the company’s data centre rather than on customers’ machines. It is set to heavily influence the future of business and home computing.