I had no idea stab-lok was still being produced.
Conceivably the guts of the breakers have been redesigned, but I think this shows Schneider (parent company of Square D) owns at least parts of what used to be Federal Pacific.
meanwhile . . .
FPE is still a very popular brand in Canada. The problems with the no trip breakers was only the USA. We never had that issue here.
I,m sure there are tens of thousands of homes in the USA with FPE boxes that have never had a problem for one reason or another. Then there are those homes that have burned with the fire marshall pronouncing the ubiquitous "defective wiring".
We have often been called to jobs to install recessed lights or what ever. It is then that we tell what they have and what needs to be done and that we cannot add circuits.
since the guts were redesigned, there shoulld not be a problem.
Where and when were the guts redesigned,and where do you get breakers that will fit an obsolete box smithy? Not sure you work in the real world.
maybe not so safe. stick to qo, the proven performer!
Here is a link that might be useful: Should Federal Pioneer Stab-Lok Electrical Panels be Replaced?