Bingo. Apples and oranges as far as breaker ratings go. You cannot apply ratings across rating agency specifications. Meaningless exercise.
I think I understand what you are attempting to do here; you don't know what is there other than the breakers and you are attempting to extrapolate an Available Fault Current based on the theory that the breakers that are being used are an indirect indicator of a minimum amount of fault current. For example if there was only 35kA available, they would not have used 65kA breaker, so you know the AFC must be over the next lowest value but not higher than the lowest stated value of any one breaker you see installed.
It's a noble attempt to do something without the proper information, but really, you cannot ASSume anything from what you have so far with regards to any reasonably accurate Arc Flash study. Whatever you extrapolate is useless when it comes to a real Arc Flash Hazard Risk Analysis. You must have REAL data on what is AVAILABLE as far as Fault Current, which has almost no meaningful bearing on what was used in the equipment design. For all you know, the equipment you have pictures of may actually have a "Series Rating" with something else up stream, so the values shown on the individual breakers themselves may be rendered meaningless in terms of what you are basing your assumptions on. For example you may actually have 85kA of AFC, but this panelboard may be rated 85kAIC when used behind some other Current Limiting breaker upstream, so that they can use 65kAIC rated components. But that will have no bearing on the AFC as far as your Hazard Risk Analysis. Sorry.
Jraef,
Thanks for taking the time to respond back to me. What you have surmised is actually not what I'm doing. I have an extremely well documented set of field reports of what is available at the site for modeling. I have model/serial number of every panel, switchboard, switch gear, transformer, etc...
My issue is much simpler than what people are making it out to be.
When inputting data into SKM Powertools for a branch breaker or a MCB... it gives you three options per type of breaker, 240v 480v or 600v. The way I understand these breakers is that they are designed for operation under 600v. This is great because our system is 400v. Well within operational parameters for the breaker. But because I can only select one of these three options in the software, I assume it is safe to say that the ACTUAL AIC rating of the device is going to be greater than whatever it is as if I have this device hooked up to a 480v system, because the lesser the voltage, the higher the AIC rating.
When I started, I assuming the lowest AIC (@600v) for the breakers because there was no information of its rating at 400v. I ended up with a good number of failures as the available fault current exceeded the ratings of a number of the panels/breakers. However, because we're at 400v, I am guessing I can safely apply the 480v printed AIC ratings to these devices as thats going to be closer to what the actual AIC rating is, but also does not go over it.
I was a bit worried that even though the Breaker's printed data had cases for 240v, 480v, and 600v, that maybe you had to use the 600v data because that's the devices maximum rating, and that there might be an identical device that tops out at 480.
I am also making an educated guess that when this system was designed, the PE actually used NEC to do so, since NEC rules apply at this particular site, and therefore things should be coordinated and have been appropriately sized in terms of ratings.
However, as we all know, nobody's perfect.
Oh, and I did go over everything yesterday and applied series ratings based on manufacturer's UL guide, which reduced a number of my failures as well.