Independent Grounds

[Speedskater]

Jim Brown just came out with a new edition of his technical paper. It expands on International power systems.

Power and Grounding for Audio and Video Systems
A White Paper for the Real World – International Version
Jim Brown - Audio Systems Group, Inc.

SurgeX® International Commissions Global AC Power and Grounding White Paper

http://soundforums.net/hub/1529-sur...ns-global-ac-power-grounding-white-paper.html

 

[Orb]

Speedskater,
Just curious how does Equi=tech and comparable power solutions work in America and what benefit is there to star grounding in the same context (appreciate all from same power-point)?
More interested from technical ground (rather than protective earth perspective) with separate spur related for audio system.

Edit:
BTW I do agree with you about issue of seperate safety/protection grounds as shown in the articles.
Thanks
Orb

 

[Speedskater]

Mr. Jim Brown covers all those points in the above 43 page paper. I would place special emphasis on the "Local Bonding" section on page 24. I like to keep the length of component to component power wires as short as practicable. Whereas a complete star connected system adds lots of wire.

For about 50 more of Jim Brown's papers & PowerPoints ( he is both the AES committee chair on EMI/RFI and a Ham radio operator) see his page:

http://www.audiosystemsgroup.com/publish.htm

 

[Orb]

Yeah I know Jim Brown - you mentioned him in the past when we both mentioned AES chairpeople hehe.
I also have his lengthy paper relating to UK.
BTW looking back I do not think we are disagreeing that much, my disagreement related to myth that a "clean earth" or a well designed (including technical ground consideration) solution beyond standard domestic setup does not benefit audio as it does.
Clean earth does not necessarily mean just plonking another rod into the ground (which as it mentions can be done but requires as you mention bonding and safety/building regulation considerations), but a complete consideration from house entry point and existing quality earth, to also wiring/isolation/technical ground of the audio/sensitive gear.
There is a subtle difference between PE and technical ground.
Anyway the company I linked specialise in providing power conditioning/isolation/transformer solutions for sensitive equipment including medical/transmission/etc.

Cheers
Orb

 

[andy_c]

It's well-known that to achieve low-noise performance in aircraft electronics, a conductive pole must be sunk into the ground, attached to a wire that runs to the aircraft and is attached to its fuselage. This can cause some occasional problems on intercontinental flights, but high-speed spooling technology has solved that.

Here's another useful grounding technique:

 

[mep]

It's well-known that to achieve low-noise performance in aircraft electronics, a conductive pole must be sunk into the ground, attached to a wire that runs to the aircraft and is attached to its fuselage. This can cause some occasional problems on intercontinental flights, but high-speed spooling technology has solved that.

Here's another useful grounding technique:

Ha ha.

 

[katylied]

So, what the expert suggest in terms of grounding of a hi-fi system to avoid safety hazard and obtain the lowest noise? I'm particularly interested in how to do for a 220/240V voltage system (as in the UK) but I guess that many would be interested also for a typical US residential installation.

 

[Orb]

So, what the expert suggest in terms of grounding of a hi-fi system to avoid safety hazard and obtain the lowest noise? I'm particularly interested in how to do for a 220/240V voltage system (as in the UK) but I guess that many would be interested also for a typical US residential installation.

There is no easy cheap solution, involves isolation and a clean technical ground, which from my experience has been done as a mesh/mat implementation (not really suitable for an existing domestic home), bringing one back to star grounding and again needs a good electrician-engineer to ensure it is done correctly and safely.
Might be worth seeing if anything in the following section: http://www.whatsbestforum.com/forumdisplay.php?305-All-Things-Power-From-the-Street-To-AC-Outlets
Here is an ongoing thread on another site just found (although concerned he feels most audio is double insulated and so reduces issue of safety ground - but I am in the UK).
http://www.avsforum.com/t/1465163/my-a-v-room

Cheers
Orb

 

[Joe D]

Thanks Speed ...that was very helpful
Joe

 

[tarquineous]

Grounding myths

It must be April 1st again!

From Henry W. Ott's big new book:

3.1.7 Grounding Myths

More myths exist relating to the field of grounding than any other area of electrical engineering. The more common of these are as follows:

1. The earth is a low-impedance path for ground current. False, the impedance of the earth is orders of magnitude greater than the impedance of a copper conductor.
2. The earth is an equipotential. False, this is clearly not true by the result of (1 above).
3. The impedance of a conductor is determined by its resistance. False, what happened to the concept of inductive reactance?
4. To operate with low noise, a circuit or system must be connected to an earth ground. False, because airplanes, satellites, cars and battery powered laptop computers all operate fine without a ground connection. As a mater of fact, an earth ground is more likely to be the cause of noise problem. More electronic system noise problems are resolved by removing (or isolating) a circuit from earth ground that by connecting it to earth ground.
5. To reduce noise, an electronic system should be connected to a separate “quiet ground” by using a separate, isolated ground rod. False, in addition to being untrue, this approach is dangerous and violates the requirements of the NEC (electrical code/rules).
6. An earth ground is unidirectional, with current only flowing into the ground. False, because current must flow in loops, any current that flows into the ground must also flow out of the ground somewhere else.
7. An isolated AC power receptacle is not grounded. False, the term “isolated” refers only to the method by which a receptacle is grounded, not if it is grounded.
8. A system designer can name ground conductors by the type of the current that they should carry (i.e., signal, power, lightning, digital, analog, quiet, noisy, etc.), and the electrons will comply and only flow in the appropriately designated conductors. Obviously false.

Henry W. Ott

I would like to add, especially to #6 above, that the earth grounding rod at a residence is intended to flow current to the grounding rod connected to the center tap of the utility transformer. This path of current is what will complete the circuit when a hot wire is shorted to a metal enclosure, thus tripping the breaker.
Since the path is always connected (no switch), it is running current in parallel with the Neutral wire, from utility transformer to house. The amount of current flowing is relative to the impedance of the earth (dirt), from the utility transformer to the ground bus in your service panel.
So what I am trying to say is the ground (earth path) is not calm electrically.