Prime Power
This is the power rating most commonly applied to diesel generators and is used in our data sheets and price lists. This is the power available at variable load if there is no main power supply. Since most applications do operate with a variable load, this rating can be chosen even if the generator is operating 24 hours per day. An overload of 10% is permitted for one hour in every twelve hours operation.

Standby Power
This is the power available at a variable load in the event of a power supply failure with a maximum utilisation of 500 hours per year. No overload is permitted. This rating is most frequently chosen when the generator is used as standby to a mains power network.

Base load Power
This is the power available for continuous full load operation. An overload of 10% is permitted for one hour in every twelve hours operation. Since it is unusual for a generator to operate at a continuous (non-variable) power output, this rating is not often selected.