Grounding Question

I do admit that I did take my schooling a long time ago but US Electrical Code has changed very little

Are you kidding??? 🤣

BUT Most equipment that doesn’t haver a dedicated ground wire/pin do utilize the Neutral side of the power cord as a pseudo ground.

@esarhaddon 

Not true now. Today if you have double insulated equipment there’s no legal/safety need to have an AC ground. The neutral and signal grounds in those pieces of gear have NO relationship.

This USED to be true with older gear and appliances like dryers, etc, however even those appliances now must be 4 prongs. My quite modern (electrically) sub has 2 prongs, but a wooden case so no chance for a short to the chassis.

I need to clarify a little.  In many cases, the chasis and signal ground are connected, so if you used a continuity tester or Ohmmeter you would see little to no reistance from the chassis to the outer shield.  Not always though, many either put a floating ground or a resistor to keep the two from being exactly the same.

But generally speaking, yes, there is a current path from the chassis to signal ground.  No, it is not a safe substitute for the AC cable ground.

Absolutely not.

The issue is the amount of current the AC cable is rated for vs. interconnects.

The AC ground is sized so that if a short to the chassis occurs it can safely blow the fuse/breaker in it or at the electrical panel.

The interconnects, and all the little printed circuit board traces are designed for nearly zero current.  A ground fault with only the ICs for grounding is likely to start a fire at the IC cable, or melt it and leave the high voltage at the chassis.