The use of tandem circuit breakers is a perfectly acceptable practice, as long as the panelboard is designed for tandem circuit breakers and they’re installed in locations within the panelboard where they’re allowed.
How many tandem breakers can you put in a 200 amp panel?
Most 200-amp breaker panels have 40 to 42 slots of single-pole breakers or 20 slots for double pole breakers. And although a 200 amp panel has many places for circuit breakers, that does not mean you can use all of it.
Limitations for Tandem Breakers In such configurations, where two hot wires feeding separate circuits share a common neutral wire, the hot wires must be connected to different hot bus bars. … Another limitation of the tandem circuit breaker is that it cannot take as much heat as a standard single circuit breaker.
