ELECTRICITY

wa8yxm is correct. The only time you will create a dangerous situation is if you use a light duty cord to bridge between a higher rated appliance (or RV) and a higher rated service. Something like a 30 amp RV adapted down to a 15 amp rated extension cord plugged into another adapter that adapts the 30 amp service down to 15 amps. That will melt the extension cord in short order. As long as your cord is suitable for the LOWER of either the RV or the outlet you plugged it into, you won't have any problems. Caveat coiling or having a rats nest of hundreds of feet of home extension cords will cause the cord to overheat and possibly melt even if 15 amps of service is not flowing through the cord. If you use a 15 amp household cord to provide service to your RV, use the shortest length possible.