I even test stuff I just built and am staring at. Anybody can make a mistake.
I second that! I used to build my own "4-boxes" to provide stage power, secure in the belief that because I knew how it should
be wired, that my hands would never get it wrong...until they did.
Would you or anyone here know of a good tester for AC wiring faults that a non-contact or "3 light" tester don't catch? I've had a couple of situations when the FAULT light on one of my Tripp-Lite Isobar power strips lights up after my simple tester shows no problem. Usually this happens when I don't have the time to pull out my DMM and refocus my mind on doing that. Is there a simple-to-use tester just for ground & neutral faults? One that I could send a well-meaning but poorly trained assistant out with?
Come to think of it, I'd pay good money for a tester that showed G-N voltage. That's something that I'm finding more of lately.