NEW YORK (PIX11) — As sweltering weather continued Monday, power crews worked to prevent black outs.

Con Edison recused the voltage by 8 percent for 100 thousand customers in Brooklyn.

A lot of times people won’t notice it,” a Con Ed spokesperson said. “Sometimes their elevator won’t be working or they may see a flicker in their lights. Some people will refer to it as a brown out.”

Utility companies asked people to avoid running their air conditioners on high. People have been asked to avoid using appliances, too.

Con Edison has invested $1 billion each year since 2005 into improving the power grid. They also store solar power in large batteries to help during outages. During weather events, such as heat waves, Con Ed brings in is all hands on deck.