This story was originally published by Grist with the headline Balcony solar took off in Germany. Why not the US? on Apr 25, ...

A circuit breaker is triggered when the S&P 500 index declines by a certain percentage within a single trading session. The three stages are: Level 1 (7% decline), Level 2 (13% decline), and Level ...

If your outdoor AC unit isn't turning on, check these switches, levels, and lines yourself, before calling for professional repairs.

Circuit breakers, or trading curbs, were first instituted for U.S. markets after the Black Monday crash of 1987, when the Dow Jones Industrial Average fell more than 22 percent in a single day.