2. misc-audio
  3. 172453-20253

Star Grounding and the Home

This comes up a bit so I wanted to talk about it.

 

You may not, for safety reasons, create a separate grounding scheme for appliances fed from the same service. May. Not. Ever. That means that at the service entrance all the grounds and the neutrals must connect, preferably with zero Ohms between them and zero Ohms to the ground rod(s). I say preferably because, corrossion, splices, etc. These are rarely perfect.

 

However, you MAY run an insulated separate ground wire to the ground rods which feed the rest of the home. This is like a star grounding scheme in a piece of audio gear. You meet the code criteria, and you hopefully dissipate noise in the ground wiring of your home at the rod before it can reach your gear. You can achieve a very good version of this by running a sub panel to your audio room.

 

One interesting possibility that I’ve seen some power conditioners hint at is to use a coil with appropriate gauge wiring and low DCR to isolate the gear. This meets the code requirements that it can carry 100% of the current in the event of a short, and the coil blocks noise from the rest of the home. Pricey, cause it requires heavy coils, and because.... audiophiles.

erik_squires
jea48
4,486 posts
 

@erik_squires Said:

If you have a different ground, it’s no longer the zero point, and when a short occurs you are no longer guaranteed it will be at 0.

In the event of a Hot 120V ground fault to an isolated dedicated ground rod the voltage WILL NEVER be zero. The Step Potential voltage around the ground rod could be as high as 120Vac.

The return path for the 120Vac ground fault current travels through the ground rod, through the earth, back to source, the Utility Power Company’s power transformer’s grounded neutral conductor. There are multiple paths provided through the earth for the ground fault current to travel back to the power transformer’s grounded neutral.

* Through the earth to the grounding electrode system of your home to the grounded neutral conductor in the electrical service equipment panel back to the source.

* Through the earth to the Utility Power Company’s driven ground rod at the transformer for connecting the neutral to earth.

* Through the earth to any of your neighbors grounding electrode systems to the grounded neutral conductor in the electrical service equipment panel back to the source.

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erik_squires OP
16,288 posts
 

If there is current flow, there must be a path.

 

The NEC grounding requirements are that in the event of a short to the chasis that path be as low an impedance as possible.

jea48
4,486 posts
 

 

thankful
211 posts

What about devices like the Puritan Audio Labs grounding Master?

You drive a second grounding rod in the ground and run a wire from that rod to the Puritan Audio Labs grounding Master and from the grounding Master to the ground on their conditioner. Are there any issues with this?

@thankful

No problem providing the AC mains branch circuit wiring EGC (Equipment Grounding Conductor) IS NOT LIFTED, BROKEN, or DISCONNECTED from the chassis of the audio equipment.

The guy in the video calls the dedicated ground rod a supplementary ground.

Added or serving as a supplement, additional...

 

 

 

 

 

 

 

 

jea48
4,486 posts
 
erik_squires OP
11,442 posts

If there is current flow, there must be a path.

 

The NEC grounding requirements are that in the event of a short to the chasis that path be as low an impedance as possible.

@erik_squires

Agree...

 

And then it says:

"The earth shall not be considered as an effective ground-fault current path."

2020 NEC 250.4(A)(5)

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