Understanding Tandem / Twin Breakers for QO Load Centers
Tandem breakers are known by different names, such as duplex, slimline, twin, half-height, half-inch, double and wafer breakers. Some may confuse tandem breakers with two-pole circuit breakers, however, tandem breakers do not get connected to two different poles at a panelboard and do not have a common trip or handle tie for simultaneous disconnecting of two poles — unlike a two-pole circuit breaker.