If I place the probe of my Rigol oscilloscope on the metal casing of the outlet box I can see a lot of noise on the scope. The noise definitely coincides with actions of nearby machines with motors running and stopping. The spikes are repetitive in regards to the specific machine, short, from 5 to 27 u sec and from +/- 8V.
Is this something I should be seeing if the ground really goes to Earth ground?
The scope is plugged into the same outlet, so it has a common ground.