Earth (isolated) ground vs. wall outlet ground.

No. It’s almost certain to violate your local electrical code. It is to ensure that circuit breakers trips when they have to. Grounding your electrical system to more than one location can cause breakers not to trip during a fault.

Lots of misunderstanding here. Let me try to simplify it:

Back in the 2 prong days, ground was indeed tied to neutral. So the chassis would be tied to the neutral. If it wasn’t, then if a hot wire touched the chassis, the chassis sat at 120V and shocked you. Some components were wired like this. Us old guys remember that often you’d get a shock from a metal part. Now we still have some 2 prong plugs, why? they are generally on simple components and the UL code allows 2 prong if they have double insulation and meet certain requirements. and I haven’t been shocked by them.

The neutral "theoretically" doesn’t need to be tied to ground. it goes all the way back to the power plant and completes the circuit....but for various reasons, if you don’t tie it to ground, it can float above ground. So your 120V outlet turns out to have 190 volts on the hot wire and 70 volts on the neutral wire (I just picked 2 numbers). So if everyone ties their neutral to ground, that never happens, and it was codified.

Problem is, with multiple unbalanced loads on a circuit, especially a long and fully loaded circuit like we used to see more of, the neutral can float above ground in certain locations locations in the house, even if tied too ground in at the box. So now maybe your chassis has 10V on it and gives you a little tingle when you touch it.

So we went to 3 wire. The ground has one function, to keep the chassis or other grounded points well connnected to a 0V ground so that if a hot wire touches the chassis, you have a path back to ground and breaker will trip (usually). a bad connection to the chassis can result in less current than will trip the breaker and you have constant current flow to ground. In this case there will be very little voltage on the chassis, just the voltage loss back to the ground. since ground wires are generally robust, that should be less than a volt and not dangerous. But if you have wet feet standing on a concrete floor you can make a good path to ground and get shocked in this scenario. that doesn’t happen very often. Safety has some components of probablility.

Now if you had seperate ground rods in the earth for neutral and ground, everything will work the same. But theoretically, the circuit sould be back to the power plant, not to ground.  so I'm sure the code requires the ground to be tied to the same ground rod as the neutral.

Jerry

Looking on my 200amp main panel I notice that the neutral (white) wire bus and the ground (bare copper) bus have continuity. Wouldn’t it be better if my interconnected rig had it’s own earth ground thereby isolating it from feedback from the neutral wires?

I really think there ought to be a law against audiophiles opening up their electrical service panel, because this comes up a lot. 🤣 And no, do not use a separate ground from the main panel.

How would one get feedback here? 🤣

The only way you ever see a voltage on the ground is if there is CURRENT on the ground, which only happens during a fault.

The neutral on the other hand is a current carrying conductor and therefore has the potential to rise above ground.

@erik_squires Indeed.

Great answers thanks.  But what of the grounding posts on much equipment, including grounding blocks and common grounding of equipment I have seen mentioned?  Are these only for systems with poor electrical grounding?

Interesting topic.  I've been asking myself these same questions for years.  My old sixty three year small house has all two prong outlets from an old fuse panel.  The only ground is through the wall to the ground rod(I assume) buried to this panel.  Always worried me if my system(somewhat expensive) would be protected, even with a Furman Power Conditioner/protector.  Some years ago I installed a "ground box" from a certain manufacturer in the UK, with grounds going to each piece of audio gear. Never trusted this set-up and the sound quality was no better.  Got rid of that and installed a dedicated ground rod just outside the wall near my systems outlet and ran a heavy gauge copper cable to that outlet only  New hospital grade three prong.  This set-up is working great.  Am I wrong to think that I will be protected from a lightning strike or such?  I am not an Electrician.

If you have hum in your system it probably is a ground issue. You should consult a licensed electrician. Multiple ground points can create voltage differential... bad. There are options if you are having noise problems, which often show up in older installations where multiple neutrals are tied together for expediency. Electricians are familiar with grounding problems, they can play havoc with computers. Maybe not so familiar with audiophile equipment, but many of the same issues. The ground stud is there for your convenience, Some of the older 2 wire components ground through the shield of the interconnect. When that is not sufficient, or an incomplete circuit, the ground stud, or a cover screw, can be of use. Most equipment in the phono side benefits from a physical ground, BTW, if you have hum from an older 2 wire turntable, turn the plug 180 in the outlet, realigning the neutral. Be careful, you can do worse than hurt yourself (or someone else). Consult a pro, and don't mess with the panel.

Great answers thanks. But what of the grounding posts on much equipment, including grounding blocks and common grounding of equipment I have seen mentioned? Are these only for systems with poor electrical grounding?

The electrical ground that comes from the service panel is for safety. Millivolts of difference in a ground potential won’t affect the safety features.

The problem with a lot of audio equipment is it ends up with multiple "ground" references, with some or no relationship to the outlet, and the transformer center taps fighting to be "correct."

The worst such problems often come from PC’s which have a very different "ground" for the electrical interconnects than the power plug. This is why proper grounding may become an issue. It has nothing to do with the quality of the wiring in the home, and yet, the quality of the ground in your home is important for life safety.

IMHO, the best configuration for high quality audio is to float the signals with no relationship to the earth/safety ground. My Luxman integrated does not use the AC ground at all. This is probably breaking US/UL regulations but as a result what I do not have is a ground loop. :D

You may notice some DAC makers make a point of touting the incoming copper connectors (USB and coax) are galvanically isolated.  Sadly, not all DACs do this.

Puritan Audio offers a product Ground Master that requires adding a seperate ground rod that connects direct to the Puritian PSM156 power conditioner. They say it is safe, any thoughts?

@yesiam_a_pirate Let me reflect on my radio broadcast engineering days: If our studios (and offices) were co-located at a transmitter site, with a broadcast tower (i.e., a giant lightning rod in the sky) on the property; we mainly grounded audio equipment and broadcast equipment to reduce or eliminate lightning damage. 99% of the time this also helped in reducing hum when connecting numerous studios full of audio equipment together with each other. Many times broadcast audio equipment also had *this* grounding lug on the rear chasis panel. Now if you had a professionally built broadcast facility; you typically had a 3" copper ground strap running between all studios; which terminated at the broadcast tower's ground system (or if you didn't have a co-located transmitter or tower, the ground was tied to the building's star ground system). When that 3" ground strap was available, each equipment chasis ground lug was tied to this ground strap (along with plugging the 3 prong AC plug in the wall for power). If lightning struck the tower, this ground strap provided an extremely low impedance ground, but more importantly it kept all equipment connected to it at the same low impedance ground potential. I still employ much of what I learned and used at broadcast facilities on my home audio and grounding system. The result is extremely low noise floors. 

To lift or not lift the pin 1 connection on an analog XLR connector is another topic related to grounding. In a broadcast facility it's almost impossible to control this issue with sometimes hundreds of XLR connections taking place (in the good ol' analog days), but since most radio stations had decent star ground systems incorporated, this most times wasn't a problem. Now almost all radio stations are wired digitally, eliminating a lot of ground loop problems. Again, this same scheme can be incorporated into home audio systems with numerous pieces of balanced analog gear interconnected. IMO it's much easier to control this in a home environment as compared to a radio station environment. Learning how to solder can be a very important skill to know when setting up a home audio system, as you'll want to be able to unsolder or solder, some of these pin 1 XLR connections when hum presents itself.   

@gs5556 

”No. It’s almost certain to violate your local electrical code. It is to ensure that circuit breakers trips when they have to. Grounding your electrical system to more than one location can cause breakers not to trip during a fault.”

This is absolutely, 100%, correct.

Do not add a separated ground to the system. In the event of fault, the circuit breaker will be bypassed by the new route to ground, stay open, and either start a fire or cause a shock.

If you chose to use the ground lugs on your equipment, the  should go to the plug where you have everything plugged in.  You could have one lead off the screw on the plug  and then a bolt nut and washer tying all your spades grounds together.  This is called a “star ground”.

if you are worried about communication between the components, don’t be.  Everything will take the lazy path the ground.  Not sideways.

but if you are going to buy a fancy box, be advised they are literally what I just described and a handful of diodes (which allow current flow in one direction).  Maybe $50 of parts.

Puritan Audio offers a product Ground Master that requires adding a seperate ground rod that connects direct to the Puritian PSM156 power conditioner. They say it is safe, any thoughts?

’Yikes!’ is a thought...