Power is slowly coming back on across the Island after a cable failure on the mainland caused power outages Friday afternoon. A spokesperson for the utility company Nstar said a cable failure in Falmouth caused the outage and the electricity company is starting up generators to restore power. Power should be fully restored by 5 p.m. According to the NSTAR outage map online, more than 6,200 NSTAR customers were affected. The cause of the failure is unknown at this time.