Is it necessary to have RV plugged into 30 amp plug while stored at home?
Assuming you are storing for the winter, we would say no. In fact, over long-term storage periods it is good to take the house batteries out and store in a dry location out of the cold.
There is probably no need to apply a charge during the actual storage period, but fully charge them just prior to re-installing them in the spring. It is only advisable to leave the RV plugged in during the storage period if the coach is equipped with one of the newer, computer-controlled battery chargers. Otherwise, there is a great risk of overcharging the batteries.