Hadley School children were back in class Thursday after having the day off Wednesday due to a power outage at the 100-year-old school.
The building's electricity went out late Tuesday afternoon when the main switch "popped," said district Business Manager Ed Cronin.
School maintenance workers and an electrician diagnosed the problem. The utility company National Grid helped locate parts to fix the switch and they were shipped to Swampscott overnight from New Jersey, the business manager said.
On Wednesday, crews repaired the electrical system and tested it and the buidling's pumps, Cronin said.
The system is operating fine, he said.
The Redington Street building's electrical and other systems are inspected each year by the town building inspector and fire department.
The electrical system is safe but old and needs updating, the business manager said.
The K-4 Hadley students will make up the cancelled day.
Superintendent Lynne Celli said "all districts have to fulfill the 180 requirement per statute. Thus, Hadley will have to make up this day."