Are they 220v appliances? Heating devices (high amperage) that are designed for 110v but running on 220v will draw more current than you expect. Verify that the plug is the round 220v plug. Do not buy and use an extension cord that is rated higher wattage than the socket.
I just went through this last week and the phone "help" and the guy in the SSA office both told me the form was not available online. So much for training....