A voting center caught fire in Bangued, Abra before dawn on Wednesday.
The Bureau of Fire Protection-Bangued said the fire at the Dangdangla Elementary School started around 4 a.m.
Nobody was injured as the school was empty at the time.
Arson investigators have yet to determine the cause and how many classrooms were affected by the fire.
Comelec Chairman George Garcia said that no automated counting machines were destroyed as they were not yet delivered to the voting center which was 70 percent destroyed.
The final testing and sealing of the ACMs were suspended as a result of the incident but will be conducted before the elections.
Garcia said voting at the school on May 12 will push through since only one polling place was affected.