If I understand your question fully, 30 and 50 Amp cable ends are different, so you'd need an adaptor to mate these. It sounds like you already have means (adaptor) to connect 30-Amp cable to house. Is that on 15- or 20-Amp receptacle?
If so I'd look at a 30-50 RV adaptor so you can also use it at campgrounds that may not have 50-Amp service.
Not sure what you mean by household electricity. My house has a 50-Amp in garage I installed to power a welder. With the right adaptor it could also power a large RV.