EE WAS CLOSING RELAY ON HOUSE FANS ON DRAGLINE. AS HE RESET THE LAST OVERLOAD BLOCK THERE WAS AN ELECTRICAL FLASH; HE WAS MOMENTARILY BLINDED. HE THEN PROCEEDED TO TAKE MOTOR LEADS OFF THE OV ERLOAD BLOCK ON THE OTHER SIDE. WHEN LEADS WERE OFF HE RESET THE BREAKER THAT WAS TRIPPED FROM THE FLASH; HE TRIED TO RESET THE OVERLOAD BLOCK AGAIN & IT FLASHED FOR THE 2ND TIME.