According to Mikepier :
I am renovating a kitchen in an apartment building in which all of the
units have Federal Pacific panels ( I know, that's a whole different
topic, the building owners are well aware of the issues with them) .
I would like to add another circuit to the panel, there is room. The
problem is do they still make replacement or aftermarket breakers for
these panels? The other option I have is to use a 2 pole breaker that
was for a 220V A/C that is not used anymore, but do I , or can I,
physically cut the pin that joins the 2 breaklers so each can operate
seperately?

Don't cut the pin. IIRC the main problems that US FPE breakers had
were duals hanging up.

FPE (as "Federal Pioneer") "StabLok" is still being manufactured.
Schneider Electric of Canada acquired the rights when Federal Pacific
went under. You can even get arc fault versions, and are still common
in new construction. FPE breakers are available in most hardware/DIY
stores here, including Home Depot, at prices just like any other
breaker.

Schneider's web site doesn't make it clear whether they distribute to
the US or not, but they do list Ace Hardware as a retailer, and I don't
think Ace is in Canada at all.

You might try:

1) Ace Hardware
2) If you live close to Canada, drop over the border to a Home
Depot or Home Hardware etc.
3) Mailorder from Canada

With an older FPE system, it seems the best thing to do is to go thru
the net and find out exactly what's problemmatic. I believe there's
two issues: US FPE 20A duals of a wide vintage, and Schneider 15A
singles of a later and very narrow vintage, and then see if your
panels have the problemmatic units and get 'em replaced.

I believe Schneider will still replace free any of the 15As of the bad
vintages.

My SIL's house recently had some major renovation work done (new
circuits, rearranging feeds etc). 1900's home, incremental wiring
replacements done over the past 50 years. FPE. Checked it out, had
none of the problemmatic breakers. System is just fine.

Given that CSA is generally somewhat more aggressive in resolving issues
like this than UL, I trust current generations of FPE. There's no
reason to believe the problems with US FPE are still around.
Besides, Schneider owns Square D too ;-)
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.