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To buy grounded or not to buy grounded. That is the question.

I recently happened on to a highly recommended web site and looked at power cord options.  There were two basic options: grounded or non-grounded.  Below is the copied info from the non-grounded cord page.

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"Description
Non-grounded cord  (Ungrounded, the ground wire is removed from cord, with G-plug still intaked)

WHY?

Based upon measurements and listening tests; I have recommended to people, to ground only one piece of their interconnected equipment. The interconnects will provide static dissipation through the secondary ground connection & nuetral. They often look at me in extreme terror.😱

Wikipedia agrees…

Wiki; A ground loop is the result of careless or inappropriate design or interconnection of electrical equipment that results in there being multiple paths to ground where this is not required, so a complete loop is formed. In the simplest case, two items of equipment, A and B, are each connected to a wall socket by a 3 conductor cable, containing a protective ground conductor. This becomes a problem when a interconnect cable is connected between A and B, to pass data or audio signals. The shield of the data cable is typically connected to the grounded equipment chassis of both A and B. There is now a ground loop.

How can you benefit from this? Purchase the Grounded cord to hook to your preamp or integrated receiver…All other power cords in the system, such as source equipment, dacs, amplifiers, subwoofers,etc. should all use the non-grounded cord.  This will direct ground your system, removing hum and reduce harmonic distortion from your system. We’ve seen multi thousand dollar power conditioners that do not fix or address this issue. The issues of ground loops are often greater then the dirtiness of the actual AC power!



Need More?

Hot: The black wire is the hot wire, which provides a 120 VAC current source.

Neutral: The white wire is called the neutral wire. It provides the return path for the current provided by the hot wire. The neutral wire is connected to an EARTH GROUND!!!

Ground: The bare wire is called the ground wire. Like the neutral wire, the ground wire is also connected to an earth ground. However, the neutral and ground wires serve two distinct purposes.

The neutral wire forms a part of the live circuit along with the hot wire. In contrast, the ground wire is connected to any metal parts in an appliance such as a microwave oven or coffee pot. This is a safety feature, in case the hot or neutral wires somehow come in contact with metal parts. Connecting the metal parts to earth ground eliminates the shock hazard in the event of a short circuit. (KEY WORD IS SHORT CIRCUIT, Meaning your electronics are broken!)"

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What think ye of this?

Toolbox149

toolbox149
spatialking's avatar
spatialking
610 posts
 
Cleeds is correct.   When equipment manufacturers put a power cord on with a third prong, they really want you to ground their unit.   Not doing so creates a safety hazard, sometime a lethal one.   Yes, if something internal fails or breaks you can have 120VAC line on the chassis, but that is not the issue of what I saying.   Internal equipment can "leak" line current through parasitic capacitance, mutual coupling, etc. which will put some AC voltage on the chassis.  Touching an ungrounded chassis with a real ground will run that current right through you. 
When you work around electronics and electricity long enough, you will get zapped sooner or later.   Early in my EE career I discovered just how conductive concrete is.  I got seriously zapped just from this, not plugging a power supply ground into a grounded outlet and standing on concrete.
The problem with that third prong is sometimes they get plugged into a different outlet than the rest of the equipment and you get a ton of hum.   There are a number of reasons for this but do what Cleeds stated - get all the grounds at the same potential.  The easiest way to do this is to power everything from one outlet box and use that ground for everything.
n80
2,107 posts
 
If a ground loop is a problem, where do you hear the hum? In the device itself? Through the speakers? Both?

I have had three sources of hum.

1) Cheap TT motor. Needs to go in trash.
2) Second hand Denon tuner. Mechanical sounding hum in the unit.Not heard through speakers. Goes away with book on top. Rarely use it.
3) One instance of hum through speakers when linking Apple TV with DAC via Toslink. Never duplicated. Don’t use this much anyway.

Otherwise, even at max volume my speakers are silent when nothing is being played.

Does this mean that there are no serious grounding or ground loop issues? My house is old but has both water pipe and copper rod grounding.
Ag insider logo xs@2x
cleeds
5,662 posts
 
n80
If a ground loop is a problem, where do you hear the hum? In the device itself? Through the speakers?
You'd hear it through the speakers and/or headphones.
even at max volume my speakers are silent when nothing is being played. Does this mean that there are no serious grounding or ground loop issues?
Quite likely, provided your safety grounds are sound.
jea48
4,310 posts
 
+ 1 what cleeds and spatialking posted.

"Description
Non-grounded cord (Ungrounded, the ground wire is removed from cord, with G-plug still intaked)
Power cord is not Listed by any 3rd party testing laboratory.

in case the hot or neutral wires somehow come in contact with metal parts. Connecting the metal parts to earth ground eliminates the shock hazard in the event of a short circuit.

It also provides a low resistive path for ground fault current to return to the source in the event of a hot Line to chassis fault. A hot to chassis fault will cause an overload in the equipment AC line fuse causing the fuse blow breaking the fault circuit. (Fault on load side of fuse) If the fault is ahead of the fuse the only protection then is the branch circuit breaker that protects the branch circuit wiring. No way, jmho, the small wire of an IC will handle possibly over a 100 amps of inrush fault current.

Based upon measurements and listening tests; I have recommended to people, to ground only one piece of their interconnected equipment. The interconnects will provide static dissipation through the secondary ground connection & nuetral. They often look at me in extreme terror.😱
Sounds good but has anyone run any tests or experienced an IC carry, handle, the ground fault current in the event of a hot to chassis ground fault? You might want to look at the wiring schematic diagram of your audio equipment. Good chance you will find the signal ground is not connected directly to the chassis.

Even if the IC can handle a high current inrush ground fault will the signal ground circuitry of say a preamp be able to handle it long enough for the AC line fuse in a power amp to blow open?
Jim
erik_squires
15,808 posts
 
Under no circumstances should you remove a power (i.e. safety) ground when the manufacturer provides for it.

Certain devices with removable cords do NOT require it, as evidenced by the IEC connector having only 2 prongs. For instance, my sub woofer.

The Pangea cables with removable ground pins are a safety hazard in multiple ways and should not be purchased or used.

You may always use a grounded cable for an ungrounded device though.


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