How they come up with the max of 150% on appliances OCPD?

[brother]

I was reading again on the NEC appliance max ocpd of name plate for non motor types. I was curious what was the history to have them come up with 150% being the max? Was this an arbitrary number, or was this tested to show this is what would be needed to help reduce damage and fires of the equipment at 150% many years ago?? Not 130%, or 145%, but 150%.