What is the first step that should be taken before filling a motor home or RV?

Turning off all appliances is essential before filling a motor home or RV to prevent potential hazards during the refueling process. Appliances can generate sparks or heat, which may pose a risk of fire or explosion, especially when dealing with gasoline or other flammable fuels. Ensuring that all appliances are switched off reduces this risk significantly and promotes safety during the refueling operation.

While the other options may also be important in their own context, they do not directly address the immediate safety concerns related to refueling. For instance, ensuring the vehicle is connected to a power source is typically less relevant during filling, as the primary focus should be on safety. Checking weather conditions can inform decisions about when to refuel but does not directly impact immediate safety during the filling process. Calibrating the filling equipment is vital for accurate fuel measurement, but it does not mitigate potential hazards associated with operating appliances in the RV.