Business owners at a South Windsor shopping plaza are hoping the power will return on Friday after a suspicious fire knocked out the lights earlier this week.

Windsor police are investigating after a pile of cardboard caught fire and affected the power to the Yorktown Square plaza at 9 a.m. on Tuesday.

Enwin Utilities crews have been working to restore the power; however, the necessary wiring wasn’t immediately available for the repairs. The appropriate supplies were ordered from Kingston and arrived on Thursday.

A dozen stores were affected at the plaza -- located at 1341 Grand Marais Rd W. -- including a hardware store, a deli, a restaurant and a hair salon.

Seven stores remain closed as the repairs are made. Some businesses are open with the help of generators, but doors have been propped open to help cool the stores in lieu of working air conditioning.

According to Chief Fire Prevention Officer, John Lee, the cause of the small fire has yet to be determined.

“We are unable to pin point the exact cause of the fire,” said Lee. “We did eliminate any electrical sources or any natural causes of the fire. As a result, we are treating it as a suspicious fire.”

The finding has left some shoppers uneasy.

Damage has been estimated at $20,000 but, that figure doesn’t include lost sales.

Enwin says an inspection needs to be completed before power is returned to the plaza.