An electrical malfunction sparked a non-injury fire at a commercial building in Miramar today, causing $600,000 in damage, authorities said.

The blaze at 7636 Miramar Road was reported around 3:40 a.m., a San Diego Fire-Rescue Department dispatcher said.

Flames shot through the roof of the building before the fire was knocked down around 4:10 a.m., he said.

Investigators determined the fire an accident caused by an electrical problem, said department spokesman Maurice Luque.

The blaze caused $500,000 damage to the contents of the building and $100,000 to the structure, Luque said.

About 25 firefighters confined the flames to a product-packaging area in the 8,000-square-foot building, which housed American Control Engineering, an electrical parts manufacturer, Luque said.

Nobody was inside the building when the fire broke out, and no injuries were reported, Luque said.