Manitoba Hydro said residents in eastern Winnipeg and the Rural Municipality of Springfield may hear loud bangs as it tests equipment early Friday afternoon.
Protection equipment on the 500,000 volt line is being tested near Riel Station on Deacon Road.
The line connects Manitoba Hydro’s network to customers in the United States.
Tests will deliberately short transmissions on that line to make sure equipment responds safely and quickly.
Those tests create a loud bang noise that can be heard far away.
Manitoba Hydro said residents should not be alarmed by the noises, and that it has notified local authorities and schools of the tests.