? on QO breakers

[theoldwizard1]

Do old QO breakers (like from the 80s) fit new QO boxes ?

I know the older QO boxes will not accept the new tandem breaker ! Luckily I found NOS.

 

[Gokart]

The old breakers will fit the new load centers.

 

[u2slow]

I have probably 60 years of QO equipment and the basic bus stabs haven't changed. I don't do much with tandems, but the rest plug and play.