NonLinearLoad, I might be missing something obvious, but how would "real testers" find the problem you describe any more then the "Snake Eyes" tester.

I have a few different meters and "wiggys"
But I always have a receptacle tester it's fast and efficient when checking large numbers of outlets. Luckily 277 volts at the receptacle is rare.

And on the keep it separate, well that would be the intent [Linked Image]

Bob Badger
Construction & Maintenance Electrician
Massachusetts