A continuous load, under 225 amps, is a total of 1 hour in any two hour period, under normal operation. If you normally operate your drier at high heat for more than one hour at a time, it might be continuous. Unless you have a commercial dryer, the element will cycle, and it probably isn't continuous. In my home, the dryer runs for a few hours on the weekend, so the normal operation is off. Since I can select "any two hour period", I'll pick a weekday. It clearly doesn't say "every" two hour period.
