ARGYLE (CBSNewsTexas.com) — After one of the hottest days of the year, Oncor plans to shut down power to homes around Argyle for several hours Friday night to upgrade equipment strained by growth and heavy demand during the summer.

The outage, scheduled for 11 p.m., will impact the same homes that lost power unexpectedly overnight Aug. 3, after a 108-degree day.

The power distribution company said it had been planning the work for several weeks, and pre-set as much equipment as possible to help complete the upgrade in five hours or less.

Residents responded to news of the plan online with some frustration, wondering why the upgrade couldn't have been completed before or after the season's hottest temperatures.

A company representative explained significant growth in the area, and an increased demand, had pushed equipment just installed a year ago to capacity. Replacing it now is necessary, or a failure could lead to an outage of up to 18 hours.

Argyle Town Administrator Erika McComis said she estimated the outage would affect about one-third of the town. Some neighborhoods to the north in Denton also expected to be impacted.

Thursday night, temperatures in Denton were still at 94 degrees at 11 p.m., when the Friday night outage is expected to begin.