Manitoba Hydro says there is no cause for concern after an underground electrical fire cut power to nearly 1,400 customers in the city's downtown for several hours on Saturday.

Some conductor lines caught fire under Main Street near Higgins Avenue just before 4 p.m., prompting the utility to cut power in the area.

The fire caused a manhole cover on the sidewalk to blow up into the air. Main Street from Higgins to Logan avenues was temporarily closed to traffic while emergency crews dealt with the fire.

Hydro cut power at around 5 p.m., affecting about 1,400 customers downtown and in the Exchange District. Officials say power was restored at around 8 p.m.

"They were able to extinguish the fire [and] transfer the power to another set of lines that run through the underground in that area," Hydro spokesperson Andrea Gruber told CBC News on Sunday.

"They'll still have to do some repairs this week, but they were able to restore power within a few hours."

Gruber said Hydro is still investigating what made the conductor line catch fire, but she noted that no work was being done on the line at the time.

She said crews are currently dealing with a number of outdated lines across Manitoba.

"We are replacing all kinds of equipment all around the province, including the underground conductors, overhead conductors that have come of age. So we are always trying to keep the power on and keep it reliable for our customers," she said.

About 40 people had to leave the Bell Hotel as a precaution on Saturday.

No one was seriously injured, but four people were taken to the hospital for possible carbon monoxide inhalation.