The fire that tore through a strip of Ballard businesses Monday was most likely caused by an overheated electrical system, Seattle Fire Department investigators determined Tuesday.

The blaze left behind an estimated $3 million in damage to the property and the contents inside, at Kitchen N Things, La Isla and Pho Big Bowl restaurants, Octo Designs & Jewelers, and Supercuts in the 2300 block of Northwest Market Street. By Tuesday morning, charred debris spilled onto the sidewalk from gaping holes where the storefronts’ windows had been, with the remnants of the collapsed roof visible inside.

Fire department working to determine cause of Ballard blaze; fund set up for affected businesses

While officials said the fire originated in the “void space between the ceiling and roof” and its cause was likely electrical, the official cause of the fire will be considered “undetermined” because of the amount of damage and the instability of the structure, fire department spokeswoman Kristin Tinsley said in a statement.

Firefighters plan to remain on the scene until the structure is no longer at risk for reigniting. Tinsley noted that a large fire wall between the jewelry store and pho restaurant helped prevent the fire from spreading farther down the block.

Four of the five businesses affected by the fire — La Isla, the kitchen store, jewelry store and salon — were believed to be total losses, while the pho restaurant sustained comparatively less damage. The fire department’s estimates are preliminary, and the businesses’ insurers will further determine the monetary amount of the damage, Tinsley said.

Meanwhile, a fund was set up to help the businesses destroyed in the blaze. The advocacy group Ballard Alliance established a GoFundMe page and donated the first $5,000. More than $20,000 had been pledged by Tuesday afternoon toward a goal of $50,000.

“Small businesses are the backbone of our neighborhood and the loss is felt by the entire Ballard community, ” Ballard Alliance Executive Director Mike Stewart said in a statement announcing the fund.