But notice I said "Switchgear", not load centers and panelboards.
Originally Posted by malachi constant
Here's the scoop. The old ITE product lines that still exist today are the Siemens "EQ" panels and their kin, using the "QP/QT" series plug-in breakers and the "BL/BQ/QJ" type bolt-in and the Sentron line of larger MCCBs. Those have not changed in 50+ years and there are UL documents available from Siemens that will show AHJs that it is perfectly acceptable to use the new breakers in old compatible ITE and Goulds/ITE load centers and panelboards. The documents list the acceptable product series.
But under the "Goulds" name, there was also what was called the "Pushmatic" product line that was Bulldog before ITE bought them, before Goulds bought ITE, before Siemens bought Goulds/ITE. Siemens no longer supports that old Bulldog product line, they killed it some time after they bought ITE because there was too much baggage (product liability). So if your "Goulds" panels say "Goulds / ITE Pushmatic", you would not go to Siemens for replacements. There are Chinese suppliers that make retrofit Pushmatic breakers. You may find some push back from AHJs on retrofitting them however, because there have been issues and most are not UL listed. Some are ETL listed but apparently not specifically for use in the old Bulldog panels because the old Bulldog panels are no longer made (don't ask me how they get away with that).
"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)