using tandem breakers for mini splits?

I have two 115v 12k Mr cool minisplits that i am wiring to a wfco 8930/50 so using tandem breakers to max out AC circuits since space is limited. seems like I read u have to use a separate circuit for each Mr cool. so I understand a separate circuit gives the full 20 amp capacity but I'm a little fuzzy on why this is ...seems to me 20 amp is 20 amp and if my breaker says 20 amp even on a tandem why couldn't I utilize it that way even for two ac units?

Each half of a tandem breaker is a separate circuit. You should be fine using one side of the tandem 20/20 breaker for one mini split and using the other side of the tandem 20/20 breaker for the other mini split.

oh great thank you! so along that line if I were to bridge the bars of the 8930 it seems like i could energize the 50 amp side and use it as extra 30 amp breaker spots...although I don't see anything like that anywhere so I'm guessing something like that would be frowned upon

Bridge the bars? Are you referring to the bus bars? Bridging them with be a direct short of 240 volts. Each side connects to a different phase of a split phase panel. Breaker spots are breaker spots and as far as I know there is no such thing as a 30 Amp breaker spot.

I don't know what the 50 Amp side is that you are talking about. Please clarify what is the 8930 and the 50 Amp side that you are talking about? Clarity is important with any electrical circuit. Do you understand what a shared neutral is using a tandem breaker? A tandem breaker is a breaker that has the levers connected and connects to each phase of a split phase panel

this panel can be wired for either 30amp or 50 amp shore power and also has a separate section to wire DC . I should've been more clear. I am running 30 amp shore power to the one leg. so the question was if you connected the two powerstrip bars together could you use the entire strip for 30 amp power? I think your reference to the tandem breaker applies to a 50 amp set up which mine will not be. as to the shared neutral on the tandem breakers I guess I don't understand since the neutrals should all go to the neutral bus bar.

@johnim
I did not see that I was in the Vehicle Mounted Systems section. Obviously it is not my area of expertise. Others can advise whether joining the two bus bars together is appropriate if the panel is only fed by a 120 v 30 Amp Shore power. . I assume that there would be some way to prevent a 240 V 50 Amp Shore power from being connected.
My apologies

johnim said:

this panel can be wired for either 30amp or 50 amp shore power and also has a separate section to wire DC . I should've been more clear. I am running 30 amp shore power to the one leg. so the question was if you connected the two powerstrip bars together could you use the entire strip for 30 amp power? I think your reference to the tandem breaker applies to a 50 amp set up which mine will not be. as to the shared neutral on the tandem breakers I guess I don't understand since the neutrals should all go to the neutral bus bar.

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I believe that usually this is done with some sort of a switch to prevent accidental shorting of a 50 amp plug in. I have never used an rv with a 50amp shore input but I always assumed that the 30amp to 50 amp dog bone would do the bridging for you. The mr cool 12 k mini split requires a 20 amp breaker. That means that the unit itself must get close to a 15 amp draw. You will have to be careful what you run in your rig if both units are running full bore. I’m sure repeated power outages are not good for mini splits.

no worries ampster. appreciate the input. as far as a 50 amp plug in issue I would guess that would only be a problem if there was a 50 amp outlet to plug into which there will not be. the minis do require a 20 amp breaker will have to see the pull on start up...hoping that as long as they don't start up at the same time it will not be an issue but if so I will probably have to add an inverter.

johnim said:

no worries ampster. appreciate the input. as far as a 50 amp plug in issue I would guess that would only be a problem if there was a 50 amp outlet to plug into which there will not be. the minis do require a 20 amp breaker will have to see the pull on start up...hoping that as long as they don't start up at the same time it will not be an issue but if so I will probably have to add an inverter.

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Don’t use the microwave when the 2 ac units are on

good point...although the only way to know for sure would be to test it out :D