When is it acceptable to use the "typical data" in the software as opposed to actual data for generators. I am working on about 40 systems each with a stand by generator (80kw to 300kw). Many of the generators are close to 25 years old and the submittals are long gone. If I go back to the manufacturer, I'm not sure if they can provide me with the data for the older units.

There are also a couple instances where the wiring to the old molded case breaker makes it impossible to get the breaker nameplate data. In order to remove the cover plate on the breaker, the feed would have to be removed. Once removed, I'm pretty sure it would have to be replaced and the customer doesn't want to touch it. For all the effort, there's a chance that breaker model isn't made any more. Is it acceptable to make an assumption and state that assumption in the study?

It's been difficult to get data on old installations.

Thanks for any help.

In this case, it might be better to state that this part can not be included in the calculations. Assuming the generator data and then assuming the C/B data is basically saying the arc flash results are also being assumed.

The only other option with generator data is to use a "typical" Xd'' and then try going higher and lower to see if the PPE results change much.

Thank you. I like your recommendation to not include in the calculations.