I am told that the 5K pot should be insulated from the chassis (not the heat sink), and that I should look for a pot with a plastic shaft. This is for safety reasons, in case some sort of AC irregularity causes current to defeat the pot's internal insulation.

Can anyone tell me where I can find a pot like that, set up to be mounted through a hole? I checked Mouser.

 

DigiKey have all kinds, make sure you get a linear version, not logarithmic.
Max.

 

This picture shows a insulated SCR's HS and holes for mounting the chassis??
Max.

 

Thanks. It turned out Mouser had something after all.


Mouser Part #:
652-95A1A-B28-A13L

 

New question: if I get a plastic project box, what do I do with the AC ground wire? Should I ground the pot case? It's conceivable that it will develop a fault and shock me. But I think that if that happens while the pot case is grounded, it might fry the board, whereas leaving it ungrounded would just result in an annoying shock and a new pot.