Guam - The entire island was left powerless last night for several hours. Guam Power Authority spokesperson Art Perez says last night's blackout was triggered by a fault on Ypao Road around 7:15.   The line fall caused the Cabras 3 and 4 plants to trip offline.

"What should have happened is that the breaker in Tamuning substation should have isolated it, but it didn't. And that led to another part of the Tamuning substation being affected; it failed to isolate and in this case with our protection system already in place, and our system already vulnerable with the loss of Cabras 3 and 4 another baseload generator unit went offline," he explained. "And those baseloads were Tanguisson 1 and 2."

GPA crews were sent out to activate backup generators and the last circuits went back online around 2:30 this morning.