When calculating facility power requirements, what percent of the permanently installed generator's load capacity should you size a generator?

When sizing a generator for facility power requirements, it is advisable to size the generator to meet no less than 50 percent of its permanently installed load capacity. This guideline is based on ensuring that the generator can handle the load without being overstressed, while also providing adequate capacity for potential future growth or additional loads that may be introduced.

Sizing a generator correctly is crucial for ensuring reliability, efficiency, and longevity. If a generator is undersized, it may run at full capacity continuously, leading to overheating, increased wear and tear, and ultimately a reduced lifespan. Conversely, sizing the generator to at least 50 percent of its capacity allows it to operate efficiently within its limits and respond effectively to varying load conditions.

Higher percentages, like 75 percent or 100 percent, could potentially limit the generator’s operational capacity, especially if there are sudden increases in load. This can lead to equipment malfunctions or failures during peak usage times. Choosing a lower percentage like 25 percent might not provide sufficient capacity for handling critical loads or future needs, thereby compromising the reliability of power supply. Hence, the recommendation to size a generator to no less than 50 percent provides a balanced approach to ensure optimal performance and reliability.