Tandem breakers, often called split breakers or double breakers, provide two separate circuits in the space of a regular sized breaker opening. Every circuit breaker panel has a limited number of circuit openings available. The problem is that when the openings are all used up and you still need to add another circuit, what do you do? You could change the electrical panel or double up circuits on a breaker, but this could place too much load on a particular circuit. So what then?
The answer that many have found is a tandem breaker. This type breaker is the same size as any other breaker, but it has its difference. This breaker sports two smaller breakers built into one regular sized breaker. Each has its own breaker switch and the breaker snaps in just like a regular breaker. With this simple innovation, you can add a circuit and protect the circuit on its own dedicated line.