A preliminary report from the Jamaica Public Service (JPS) has revealed that its Hunts Bay-Rockfort line failed to isolate lightning-induced faults during adverse weather conditions last week, triggering a disastrous all-island blackout from Friday into Saturday.

The 38-page report, released yesterday, said the island had 635.9 megawatts (MW) of electricity, while the actual demand from customers was 544.3 MW, leaving a comfortable safety margin, or spinning reserve, of 91.6 MW.

However, it said although the grid was functioning normally, heavy rain, lightning and lingering Sahara dust had already caused several temporary power trips in the hours leading up to the main failure on June 5 at 9:02 p.m.