Also, if the breakers were part of a UL listed MCC bucket assembly, they might be (probably are) "Mag-only" breakers (aka MCPs), UL "recognized" (UR) only to be used specifically in a listed motor starter assembly. If you don't have the starter, those breakers CANNOT be used as feeders to another device, i.e. your VFDs. They will not have thermal trip elements and are NOT UL listed by themselves.
