Help-AC input connected directly to case!

[schubert]

Originally Posted by VictoriaGuy

You need a decent ground reference for troubleshooting....either a proper earth ground at your workbench (direct connection to good ground rod) or (better) a connection to the ground of your AC house supply.
'Cheater' plugs assume that the wall box is grounded and connect to the faceplate screw...so that is one place to look.

With 'modern' plumbing, it's not a sure thing that you can get an earth ground from a plumbing connection - too many ways that you can get a plastic 'break' in the line, IMO.

I could use the "third wire" connection in the outlet above my "workbench" (which much to my wife's chagrin doubles as the kitchen counter), for it's a new outlet and the ground is connected to a rod buried in the earth right below the circuit breaker box in the garage.