ILOILO CITY, Philippines — A snake that wandered into the switch yard of the island’s power grid caused an eight-hour blackout in most of Panay Island yesterday.

In its initial advisory, the National Grid Corp. of the Philippines (NGCP) said that a fault along 138KV line in Dingle was reported at around 12:09 a.m.

It caused Panay Energy Development Corp. (PEDC) units 1 and 2 to trip while PEDC unit 3 was on preventive maintenance.

Power transmission services in Iloilo, Capiz, Aklan, Antique and Guimaras were restored at 8:07 a.m.

In its advisory, NGCP monitored a grid disturbance that resulted in the power interruption.

“Upon inspection of NGCP linemen, the root cause of the outage was a snake intrusion at NGCP’s Dingle substation which affected the Dingle-Barotac Viejo 138kV lines 1 & 2,” the statement said.

The snake intrusion resulted in the emergency shutdown of transmission lines 1 and 2.

Michelle Visera, NGCP regional corporate communications officer in Western Visayas, said the snake was found dead inside the Dingle substation switch yard.

She said they could not ascertain how the snake penetrated the switch yard since the area is enclosed with a screen and a net to prevent intrusion of stray animals.

It was theorized that the snake made its way to the yard’s power breaker where it was electrocuted. It was later found on the floor directly under the breaker.

In some parts of Iloilo City, power was restored after more than three hours, only to be cut off a few minutes later.

At around 4 a.m., the Panay Electric Co. (PECO) restored the power supply on some of its substation and feeders after sourcing supply from the Panay Power Corp. (PPC) diesel backup power plants.

PECO said power supply in some areas in Iloilo City was not immediately restored since the firm was still waiting for supply from the backup diesel plants of PPC, under the Global Business Power.

The company also appealed to the public for understanding, saying the power interruption was beyond its control.