Prime and standby generator ratings.
Understand what PRP and ESP mean when comparing diesel generators, and why a rounded model name is not the generator’s operating rating.
Prime power — PRP
Prime power is intended for a generator supplying a varying electrical load under the manufacturer’s stated conditions. The permissible load profile, average loading and any overload provisions must be checked against the actual engine and generator specification.
Emergency standby power — ESP
Standby ratings relate to emergency backup use under stated limits. A standby kVA number should not be assumed to be the output available for ongoing regular operation.
Compare like with like
Compare the same duty, voltage, phase and frequency. A 110 kVA standby set may have a 100 kVA prime rating; those two figures describe different operating duties. Some configurations publish only a prime figure, so a separate standby value must be confirmed.
How GenPro names its range
GPS model numbers use a rounded catalogue class to keep the range easy to navigate. The actual prime and standby kVA and kW are listed independently. For example, a GPS30PS name describes a canopied Perkins model in the 30 kVA class, not a guarantee of 30 kVA under every duty or connection.
Compare generator specifications or ask our team about your operating duty.