Manila, May 18 -- Speaker Faustino "Bojie" Dy III and Senior Deputy Speaker Ferdinand Hernandez on Monday filed a resolution seeking a congressional inquiry into the back-to-back tripping of major transmission lines operated by the National Grid Corporation of the Philippines (NGCP) that triggered red and yellow alerts in the Luzon and Visayas grids.

House Resolution No. 1024 calls for an investigation, in aid of legislation, into the May 13 tripping of the 500-kilovolt Tayabas-Ilijan and Dasmari nas-Ilijan transmission lines that resulted in the sudden loss of more than 2,462 megawatts of power.

The massive disruption forced NGCP to implement Manual Load Dropping, affecting around 3.9 million customers in Metro Manila, Batangas, Bulaca...