Yesterday's 90-minute power outage here in Portsmouth was due to a piece of failed equipment, according to National Grid spokesperson David Graves. About 7,600 customers experienced an outage when the circuit-breaker-like device failed, but power was restored by 7:56pm, Graves said.

The region did see higher electricity usage yesterday because of the temperature, said Graves, but there was no way to tell if this was a contributing factor. "These devices can fail from time to time," said Graves. "It's impossible to say if the increased demand caused the failure."