[A/S] a/c & microwave question

["Tricia & Conrad Holsomback" <triconholsomback@xxxxxxxxxxxxx>]

Hi Listies,
Our microwave and A/C are on a switch which allows only one to operate
at the same time.  Is that the case with all airstreams, or only some?
Our son has an SOB which only has a  30 amp hook up like us, and his a/c
and microwave can be used simultaneously. 
We have another outlet that we could use for our microwave, but we need
to know if there is a reason it is set up this way.
Tricia & Conrad