I am being told that if i have a panel that has 10k AIC rated breakers and by calculation i have 30kA short circuit at the panel, that i can install current limiting fuses ahead of the panel to effectively lower the calculated short circuit to under 10k aic. i cannot find anything in support of this. Has anyone heard of this? Ideas?
Not just any current-limiting fuse, but a class of current-limiting fuse that is a listed series combination with the brand-specific and product-family specific breaker in question, will allow you to take credit for the fuse protecting the breaker, and the breaker can be installed at a location where the fault current would otherwise be in excess of its KAIC rating. The breaker manufacturers will show series combination ratings between models of breakers in their own catalogs, as well as with fuse classes in general. The fuse class can come from any brand, provided it has that particular UL class specified for the breaker. It is rare (if ever) that breakers are series-rated with breakers of other brands, but the fuse class series ratings are fuse-brand agnostic.
An example of a series-rated combination, is Square D QO and QOB breakers (10 KAIC rated), series-rated with class J fuses (200 KA rated).