Originally Posted by rthibodaux
I am on my 3 fw, and never seen one with space for another breaker, they just don't do it, .
It's going to vary from RV to RV. The 2011 330RLTS (yes, I know it's a TT) has one empty space that can hold a double half pole breaker module and a single pole breaker that can be replaced with a double half pole breaker module. Some brands of panels can accept single half pole breakers but, since Jayco use the double half pole breaker modules, I suspect that is all that is available for them.
This is an example of a single pole breaker:
This is an example of a double half pole breaker module:
Both half poles can be either 15A or 20A only or a combination of a 15A and a 20A breaker. If your panel has an empty slot, you can add up to two circuits in that slot. If none of the slots are empty but you have at least one single pole breaker, by replacing the single pole breaker with a double half pole breaker module which will give you one additional circuit for each single pole you replace.
There is also a possibility your RV will have an unused circuit you could steal from. For example, if it is wired for two A/Cs and you have only one, you could disconnect the wiring for the unused A/C location from the breaker (I would just cap off the wire and tuck it to one side instead of cutting it off in case you ever decide to add the second A/C or sell the RV) and use that breaker for your new circuit.