Originally Posted by Kuba
Backup power for home appliances etc. For example if you had a bunch of car batteries and wanted an inverter to run any home appliances of the batteries in case power goes out(110-120v AC). You are good to go and have nothing to worry about.
I get that but the point of my question was particular to this case..
The Op is asking about a particular scenario in his/her RV. They also stated that this is a motor home so the potential for noise on a ground if left floating is very high.
Now I may be understanding something wrong here as well...If by "CPAP" the Op meant "Coffee Pot And Percolator", then by all means forget the ground...It's not worth the trouble..But if the Op was referring to CPAP as in a "Continuos Positive Air Pressure" Breathing Apparatus, then it's worth the trouble to keep any ground noise from damaging this expensive piece of medical equipment.