Are actual RV extension cords safe to use with the mobile charger (14-50 adapter). Our outlet reaches but it is like 5 feet too short of where its ideally located which makes us do a few 3 car maneuvers to get it to work with all the cars. Was hoping to get a 25 foot 14-50 cable and use the slack to get the cables out of the way. Is this any safe? Will be plugging it in almost all the time.