Wiring a detached sun room 25 feet from the house. Have 2-15 amp circuits ran to the building. Can I use a double pole snap switch located on the out side of the house for the sunroom disconnect?
You will need to use a double pole breaker at the supply and make it one multiwire branch circuit. The code prohibits more than one branch circuit run to a detached structure or building.
Also it is a violation to run two circuits through the same double pole switch, making it a MWBC fixes this issue as well.
The location of the switch can be inside or outside the detached structure nearest the point of entrance of the conductors. Just like a service.