Hydro Ottawa says some 30,000 customers are affected by the power outage. (Giacomo Panico/CBC)

Hydro Ottawa says a power outage that left some 30,000 customers without power Wednesday afternoon is due to a loss of supply from the provincial grid.

The outage happened Wednesday afternoon in the Old Nepean and Barrhaven neighbourhoods, on the same day much of the downtown was in lockdown because of the shootings at the War Memorial and Parliament Hill.

The energy provider said the outage had nothing to do with the shootings.

At about 2:30 p.m., Hydro Ottawa said about 20,000 customers were still affected as they worked to restore power.