Power has been restored to all Hawaiian Electric Co. customers affected by a widespread power outage this evening.

The first report of the outage was at about 7:45 p.m. Power was fully restored at 8:30 p.m. in affected areas including Manoa, Kaimuki, Palolo and portions of Kahala.

An estimated 20,000 customers were affected by the outage, HECO said.

HECO said the exact cause is still being investigated, but a preliminary review shows the outage started after an equipment malfunction at a Palolo electrical substation.