You ever deal with an Oscilloscope with a ground-loop problem?
You're not teaching electrical theory in 10 minutes. No sir, no way. I'm going to guess that it takes you more than 10 minutes to adequately explain what a ground loop is, even if the other guy is reasonably trained in electrical theory.
EDIT: Recognizing a ground-loop, understanding where it comes from (Oh, X device isn't grounded and my Y device ground is the Oscilloscope's ground right now), and finally solving it (switching to AC mode if you're cool with capacitive coupling).
And it can be rather dangerous / fire hazard / electrical hazard if you made a stupid choice (ex: connect X's ground to Y's ground. Are you sure there's no serious voltage difference here? After all, if there wasn't a voltage difference, you probably wouldn't be having a ground loop problem to begin with)
You're not teaching electrical theory in 10 minutes. No sir, no way. I'm going to guess that it takes you more than 10 minutes to adequately explain what a ground loop is, even if the other guy is reasonably trained in electrical theory.
EDIT: Recognizing a ground-loop, understanding where it comes from (Oh, X device isn't grounded and my Y device ground is the Oscilloscope's ground right now), and finally solving it (switching to AC mode if you're cool with capacitive coupling).
And it can be rather dangerous / fire hazard / electrical hazard if you made a stupid choice (ex: connect X's ground to Y's ground. Are you sure there's no serious voltage difference here? After all, if there wasn't a voltage difference, you probably wouldn't be having a ground loop problem to begin with)