Just get out your ohm meter or continuity tester and check. If you get continuity or low resistance (like a few ohms), that is the ON position. Put a little dot on the case as a reminder. I assume there's a KEY way in the threaded mount? Once you figure out which way is on they should all be the same.How do you know which way up to mount the breaker switches supplied by Van's such that "down" is "off" per US convention? Jim Sharkey RV6 - Getting there!